Heterologous expression of MTs in
Abstract
Metal ions are the least sophisticated chemical species that interact or bind to biomolecules. The yeast Saccharomyces cerevisiae represents a versatile model organisms used in both basic and applicative research, and one of the main contributors to the understanding of the molecular mechanisms involved in the transport, accumulation, and homeostasis of heavy metals. With a negatively charged wall, the yeast cells are very good biosorbents for heavy metals. In addition to biosorption, the metabolically active cells take up heavy metals via the normal membrane transport systems. Once in the cell, the toxicity of the heavy metals is controlled by various mechanisms, including sequestration by metal-binding proteins, such as the metallothioneins. Metallothioneins are cysteine-rich proteins involved in the buffering of excess heavy metals, both essential (Cu and Zn) and nonessential (Cd, Ag, and Hg). S. cerevisiae has two innate metallothioneins, Cup1 and Crs5, intensively investigated. Additionally, S. cerevisiae served as a host for the heterologous expression of a variety of metallothioneins from different species. This review focuses on the technological implications of expressing metallothioneins in yeast and on the possibility to use these transgenic cells in heavy metal-related biotechnologies: bioremediation, recovery of rare metals, or obtaining clonable tags for protein imaging.
Keywords
- metallothionein
- Saccharomyces cerevisiae
- heavy metal
- bioremediation
1. Introduction
Biotechnology, which makes use of living organisms for technological purposes, is one of the applied fields that constantly benefited from the rapid advancements made in understanding life at molecular level. It is undoubtedly that the budding yeast
Metallothioneins (MTs) represent one of the numerous examples of proteins whose functions were investigated by heterologous expression in
Heavy metals belong to a group of nondegradable chemicals naturally present in the environment. Numerous anthropogenic activities, especially the ones related to massive industrialization, intensive agriculture, or rapid urbanization led to important perturbations (accumulation, or in some cases, depletion) in heavy metal balance, with ecological, nutritional, and environmental impacts [4–10]. Some of the heavy metals (Co, Cu, Fe, Mn, Ni, and Zn) are essential for life in trace amounts, playing a pivotal role in the structure of enzymes and other proteins. Other heavy metals (Cd, Sb, Cr, Pb, As, Co, Ag, Se, and Hg) albeit not essential, interfere easily with the metabolism of essential heavy metals, competing for the various physiological transport systems as well as for the biomolecules they bind to. Essential or not, when present in high concentrations, heavy metals are strongly deleterious to living organisms due to nonspecific binding to proteins, often inducing oxidative stress, or disrupting biological membranes. Defense mechanisms against nonphysiological concentrations of heavy metal ions include excretion, compartmentalization in cell organelles, or increased synthesis of metal-buffering molecules, such as the MTs.
2. Innate and heterologous expression of MTs in S. cerevisiae
Apart from being classified on the basis of their structural homology or on taxonomic criteria, MTs are also classified on molecular functionality grounds, starting from their innate metal-binding abilities, into Cu(I)- and Zn(II)-thioneins, with the representative nonessential models Ag(I) and Cd(II), respectively [3, 17]. This is based on the formation of homometallic MT species when they are produced in metal-enriched media; this classification is not regarded as absolute, since cross-affinity is often noticed for Zn(II)-thioneins binding Cu(I) and vice versa [3].
Considered a secondary copper-resistant agent in
Following the discovery and characterization of Cup1, many newly discovered MTs were characterized by heterologous expression in
MT expressed | Source organism | Behavior in | Reference |
---|---|---|---|
Model plant organisms, metal nonaccumulator | Complement Cu(II) and Cd(II) sensitivity of a | [29, 30] | |
Technical plant: biofuel production | Complements Cu(II) and Cd(II) sensitivity of a | [31] | |
Technical plant: nutritional oil. Seeds tend to accumulate Cd(II), Pb(II), and Hg(II) | Complement Cu (II) (all), Cd(II) ( | [32, 33] | |
Cd(II)/Zn(II) hyperaccumulator | [35] | ||
Cu(II)-hypertolerant plant | Restore Cd(II) and Cu(II) tolerance to yeast sensitive strains | [36, 37] | |
Confers tolerance to Cd(II), H2O2, and ethanol | [38] | ||
Confers tolerance to Zn(II) | [39] | ||
Confers vigorous growth under surplus CuCl2, FeCl2, NaCl, NaHCO3, and H2O2 | [40] | ||
Alkaline/saline tolerant grass | Tolerance to H2O2, NaCl, NaHCO3, Zn(II), Fe(II), Fe(III), Cd(II), Cr(VI), and Ag(I); sensitivity to Mn(II), Co(II), Cu(II), Ni(II) | [41] | |
Alkaline tolerant grass | Tolerance to salinity, alkaline conditions, and oxidative stress | [42] | |
Alkaline/saline tolerant plant | Tolerance to Cd(II), Zn(II), Cu(II), and NaCl stresses; increased accumulation of Cd(II), Zn(II), NaCl, but not of Cu(II) | [43] | |
Arbuscular mycorrhizal fungus; confers heavy metal tolerance to exposed plants | Complements Cu(II) and Cd(II) sensitivity of a | [44] | |
Ectomycorrhizal fungus; confers heavy metal tolerance to exposed plants | Complement Cu(II) and Cd(II) sensitivity of | [45] | |
Ectomycorrhizal fungus; confers heavy metal tolerance to exposed plants | Complements Cu(II) and Cd(II), but not Zn(II) sensitivity. | [46] | |
Complement Cu(II) sensitivity | [47] | ||
Growth inhibitory factor (GIF) | Confers metal resistance to yeast cells | [48] | |
Canonical Zn(II)-thionein | Complements Zn(II) sensitivity | [33] | |
Clonable tag for electron microscopy | [82] | ||
Increased Cu(II) tolerance and capacity to remove Cu(II) when expressed from yeast | [72] |
In plants, the first evidence for the role of MTs in Cu(II) and Cd(II) tolerance was provided by expressing two
Other MTs studied in yeast were isolated from heavy metal hypertolerant or hyperaccumulating plants. Hyperaccumulating plants belong to a small group of species capable of growing on metalliferous soils without developing toxicity symptoms [34]. The MTs from the intensively studied hyperaccumulator
Expression of plant MTs in
Often, plants acquire heavy metal tolerance when growing on contaminated sites due to symbiosis with the radicular, arbuscular mycorrhizal fungi that penetrate the cortical cells of the roots of a vascular plant; one MT isolated from such fungus,
Studies on animal MTs expressed in yeast are less numerous [33, 47, 48, 72] and are used mainly for technical purposes. One notable example though is mouse
3. Biotechnological relevance of MTs expression in S. cerevisiae
The main function of MTs resides in their structure: small proteins with a significant number of cysteine residues (15–30% of the total amino acid number) [53], a characteristic that confers them a remarkable capacity to bind heavy metal ions by forming metal-thiolate clusters. MTs are natively bound to Cu(I) or Zn(II), exhibiting various affinities for the two metals, in between the canonical Cu(I)-thionein (
With high thermodynamic stability combined with kinetic lability, MTs are important candidates for biotechnology applications. In the nonmetalate form, MTs are highly reactive and can virtually bind to any d10 metal [53], a trait that makes them interesting candidates for biotechnology. In this case, two aspects of MT reactivity are highly relevant: (1) metal uptake and release and (2) metal exchange [54]. Due to the polydentate thiolate nature of all MTs and their high affinity for most heavy metal ions, there are data available for binding of Cu(I), Cu(II), Cd(II), Hg(II), Ag(I), Au(I), Bi(III), As(III), Co(II), Fe(II), Pb(II), Pt(II), and Tc(IV) [55]. Another important feature of MT reactivity is the dynamic behavior, with metal uptake and release between species of different degrees of metalation. It is widely accepted that the binding of metal ions to MTs occurs rapidly, between 10 and 30 min, although longer stabilization times are required for certain ions, such as Hg(II) or Pb(II) [3].
Studies on metal exchange in MTs have also been done (usually with either Zn(II)- or Cu(I)-thioneins), starting with a metal-loaded MT forced to exchange its initially bound metal ions with other ions. Considering the series of affinity order of heavy metal ions for the thiolate ligands: Fe(II) ≈ Zn(II) ≈ Co(II) < Pb(II) < Cd(II) < Cu(I) < Au(I) ≈ Ag(I) < Hg(II) < Bi(III) [56], the Zn(II)-loaded MTs would be more reactive than Cu(I)-loaded MTs. It was noted that metal exchange occurs at a much slower pace than metal binding to apo-MTs. For example, it was revealed that binding of four equivalents of Cu(I) to Zn(II)-Cup1 required a stabilization time of 24 h to produce a mixture of Cu4-Cup1 and Cu8-Cup1 species by total displacement of the initially bound Zn(II) [3, 57]. It is interesting to note that many xenobiotic metal ions (Cd(II), Pb(II), and Hg(II)) show higher affinity for thiolate ligands than Zn(II) or Cu(I) does, and thus, in case of intoxication, MTs can work as detoxifying agents [53]. This is highly relevant especially when designing a biotechnology system aimed for removal of toxic ions, as in the case of bioremediation. In the following paragraph, studies on metal accumulation by MTs expressing
Metal investigated | Expressed MT | MT provenience | Yeast gained characteristics due to expression of MT | Reference |
---|---|---|---|---|
Cd(II) | Cup1/His6 Yeast surface display | Cd(II) tolerance, Cd(II) increased adsorption; selectivity against Cu(II) | [66] | |
Cd(II) | Δ1–8Cup1 (Δ1–8Cup1)4 (Δ1–8Cup1)8 Surface display of tandem repeats of head-to-tail yeast MT lacking the first 8 amino acids | Cd(II) tolerance and adsorption were dependent on the number of tandem repeats; 4 and 8 repeats determined increased Cd(II) adsorption/recovery 5.9 and 8.9 times, respectively | [67] | |
Cd(II) | Yeast surface display | (Cd(II)/Zn(II) hyperaccumulator) | Increased Cd(II) tolerance and adsorption; concentration of Cd(II) from ultra-trace media; selectivity to Cd(II) against Cu(II) and Hg(II) | [69] |
Cd(II) | (Cd/Zn hyperaccumulator) | Increased Cd(II) tolerance and accumulation | [76] | |
Cd(II) | Alkaline/saline tolerant plant | Increased Cd(II) tolerance and accumulation | [43] | |
Cu(II) | hMT2, GFP-hMT2 | Increased Cu(II) tolerance and capacity to remove Cu(II) when expressed from yeast | [72] | |
Zn(II) | Increased accumulation of Zn(II) | [30] | ||
Zn(II) | Alkaline/saline tolerant plant | Increased Zn(II) tolerance and accumulation | [43] |
3.1. Display of MTs on the surface of S. cerevisiae cells
Cell surface engineering has wide applicability due to the fact that virtually any protein can be produced and autoimmobilized on the cell exterior of an engineered cell (usually a microorganism).
Adsorption of heavy metal ions at the cell surface has certain advantages compared to intracellular accumulation. First, surface adsorption allows recycling of the adsorbed ions, whereas intracellular accumulation necessitates disintegration of the cell for extraction. Second, surface adsorption is possible even in nonviable cells, providing that sufficient biomass can be produced. This is particularly important when cells are used to remove heavy metals from contaminated waters, and the conditions necessary to sustain living cells are difficult to achieve. And third, surface-engineered yeast cells can be used repeatedly as bioadsorbents since the recovery and treatment of the heavy metal ions does not greatly damage the cells [66]. In a sequel study, Cup1 was expressed as tandem head-to-tail repeats of the yeast MT lacking the first 8 amino acids (known to be nonsignificant for metal binding). Three types of constructs that were surface displayed contained 1, 4, and 8 tandem MT repeats [67].
The transgenic cells obtained were tested against excess Cd(II), and it was revealed that the adsorption and recovery of Cd(II) on the cell surface was increasingly enhanced with increasing the number of tandem repeats under conditions that allowed complete occupation of the Cd(II)-binding sites in the MT tandem repeats. Considering the relationship between cell-surface adsorption and protection against heavy metal ion toxicity, the tolerance of these surface-engineered yeasts to Cd(II) was found to be also dependent on the number of displayed MT tandem repeats, indicating that the characteristics of surface-engineered yeasts as a bioadsorbents correlated with the ability of the displayed proteins to bind metal ions [67]. Unfortunately, these promising studies soon came to a halt and no other metal ions or other MTs were taken into consideration to be used in this technique. It took ten years before another group displayed at the surface of yeast cells four type-2 MTs from
3.2. MT-expressing S. cerevisiae cells for bioremediation
Heavy metal bioremediation is an appealing approach for decontaminating polluted environments, especially because standard physico-chemical methods are ineffective and very often a source of pollution themselves [5]. An ideal heavy metal bioremediator would have certain metal-related characteristics: tolerance to high concentrations, increased accumulation, and substantial biomass production for effective removal of heavy metal ions from the contaminated sites. These traits fall into the characteristics of the heavy metal hyperaccumulating plants, with the exception that they usually do not produce sufficient biomass [70].
3.3. Heterologous expression of MTs from heavy metal hyperaccumulators
The natural heavy metal hyperaccumulators, mostly belonging to a small group of plants [34, 70], are the species whose metal-related characteristics initially prompted the ideas of bioremediation, biomining, and bioextraction. To accumulate heavy metals without developing toxicity symptoms, these organisms utilize a variety of chemical ligands capable of coordinating the metal ions in a nontoxic form. Although MTs are important candidates for sequestering heavy metal ions, the studies relevant for correlating MT expression with heavy metal accumulating phenotype are scarce and hardly encouraging [74, 75]. The examples of MT from hyperaccumulating organisms expressed in yeast are few, and they mainly focus on functional complementation tests [33, 36–38, 69, 76]. One example is worth mentioning here though, as it deals with an unusual hyperaccumulating phenotype: Ag(I)-hyperaccumulation due to three distinct MT genes of the ectomycorrhizal fungus
3.4. Metallothionein as clonable tags
Due to their small size and metal-binding capacity, metallothioneins may be interesting candidates for tagging proteins for imaging, especially by electron microscopy (EM) [79–81]. Localization of proteins in cells or complexes using EM relies upon the use of heavy metal clusters, which can be difficult to direct to sites of interest. For this reason, a metal-binding clonable tag, such as it is green fluorescent protein (GFP) for light microscopy, has been pursued for a long time, and would be unvaluable for imaging by EM techniques. In this respect, MT is a very good candidate, because instead of fluorescing like GFP, it would initiate formation of a heavy metal cluster adjacent to the protein to be analyzed. A suitable clonable tag for EM is expected to have certain properties: small size and low molecular weight, so as not to disrupt protein kinetics/function
4. Concluding remarks
The numerous studies on MTs stand for the uniqueness of these small proteins whose undisputed trait is binding to heavy metal ions. This is evidently due to the cysteinyl residues, which represent more than 20% of the total number of MT amino acids, whereas the usual percentage of cysteinyl residues seldom surpasses 5% in most proteins. The intrinsic characteristic of sequestering metal ions in thiolate clusters make MTs very interesting biomolecules for various biotechnological application. Since
Acknowledgments
The authors received funding from the Romanian—EEA Research Programme operated by the Ministry of National Education under the EEA Financial Mechanism 2009–2014 and Project Contract No 21 SEE/30.06.2014.
References
- 1.
Feldmann H. Yeasts in biotechnology. In: Feldmann H, editor. Yeast: Molecular and Cell Biology. 2nd ed. Wiley-Blackwell, Weinheim, Germany; 2012. pp. 347-371. ISBN: 978-3-527-64486-5 - 2.
Capdevila M, Atrian S. Metallothionein protein evolution: A mini assay. Journal of Biological Inorganic Chemistry. 2011; 16 :977-989. DOI: 10.1007/s00775-011-0798-3 - 3.
Palacios O, Atrian S, Capdevila M. Zn- and Cu-thioneins: A functional classification. Journal of Biological Inorganic Chemistry. 2011; 16 :991-1009. DOI: 10.1007/s00775-011-0827-2 - 4.
Prasad MNV, editor. Heavy Metal Stress in Plants. From Biomolecules to Ecosystems. Berlin, Heidelberg: Springer Berlin Heidelberg; 2004. p. 454. DOI: 10.1007/978-3-662-07743-6 - 5.
Bradl H. Heavy Metals in the Environment: Origin, Interaction and Remediation. Vol. 6. 1st ed. London: Academic Press; 2005. p. 282. ISBN: 9780120883813 - 6.
He ZL, Yang XE, Stoffella PJ. Trace elements in agroecosystems and impacts on the environment. Journal of Trace Elements in Medicine and Biology. 2005; 19 :125-140. DOI: 10.1016/j.temb.2005.02.010 - 7.
Kim HS, Kim YJ, Seo YR. An overview of carcinogenic heavy metal: Molecular toxicity mechanism and prevention. Journal of Cancer Prevention. 2015; 20 :232-240. DOI: 10.15430/JCP.2015.20.4.232 - 8.
Jan AT, Azam M, Siddiqui K, Ali A, Choi I, Haq QM. Heavy metals and human health: Mechanistic insight into toxicity and counter defense system of antioxidants. International Journal of Molecular Sciences. 2015; 16 :29592-29630. DOI: 10.3390/ijms161226183 - 9.
Caito S, Aschner M. Neurotoxicity of metals. Handbook of Clinical Neurology. 2015; 131 :169-189. DOI: 10.1016/B978-0-444-62627-1.00011-1 - 10.
Wu X, Cobbina SJ, Mao G, Xu H, Zhang Z, Yang L. A review of toxicity and mechanisms of individual and mixtures of heavy metals in the environment. Environmental Science and Pollution Research International. 2016; 23 :8244-8259. DOI: 10.1007/s11356-016-6333-x - 11.
Van Ho A, Ward DM, Kaplan J. Transition metal transport in yeast. Annual Review of Microbiology. 2002; 56 :237-261. DOI: 10.1146/annurev.micro.56.012302.160847 - 12.
Ratherford JC, Bird AJ. Metal-responsive transcription factors that regulate iron, zinc, and copper homeostasis in eukaryotic cells. Eukaryotic Cell. 2004; 3 :1-13. DOI: 10.1128/EC.3.1.1-13.2004 - 13.
Massé E, Arguin M. Ironing out the problem: New mechanisms of iron homeostasis. Trends in Biochemical Sciences. 2005; 30 :462-468. DOI: 10.1016/jtibs.2005.06.005 - 14.
Eide DJ. Homeostatic and adaptive responses to zinc deficiency in Saccharomyces cerevisiae . The Journal of Biological Chemistry. 2009;284 :18565-18569. DOI: 10.1074/jbc.R900014200 - 15.
Reddi AR, Jensen LT, Culotta VC. Manganese homeostasis in Saccharomyces cerevisiae . Chemical Reviews. 2009;109 :4722-4732. DOI: 10.1021/cr900031u - 16.
Reddi AR, Leung E, Aranda K, Jensen LT, Culotta VC. The effect of phosphate accumulation on metal ion homeostasis in Saccharomyces cerevisiae . Journal of Biological Inorganic Chemistry. 2010;15 :1051-1062. DOI: 10.1007/s00775-010-0664-8 - 17.
Valls M, Bofill R, Gonzalez-Duarte R, Gonzalez-Duarte P, Capdevila M, Atrian. A new insight into metallothionein (MT) classification and evolution. The in vivo and in vitro metal binding features of Homarus americanus recombinant MT. The Journal of Biological Chemistry. 2001;276 :32835-32843. DOI: 10.1074/jbc.M102151200 - 18.
Thiele DJ. ACE1 regulates expression of theSaccharomyces cerevisiae metallothionein gene. Molecular and Cellular Biology. 1988;8 :2745-2752. DOI: 10.1128/MCB.8.7.2745 - 19.
Welch J, Fogel S, Buchman C, Karin M. The CUP2 gene product regulates the expression of theCUP1 gene, coding for yeast metallothionein. The EMBO Journal. 1989;8 :255-260 - 20.
Buchman C, Skroch P, Welch J, Fogel S, Karin M. The CUP2 gene product, regulator of yeast metallothionein expression, is a copper-activated DNA-binding protein. Molecular and Cellular Biology. 1989;9 :4091-4095. DOI: 10.1128/MCB.9.9.4091 - 21.
Butt TR, Sternberg E, Herd J, Crooke ST. Cloning and expression of a yeast copper metallothionein gene. Gene. 1984; 27 :23-33. DOI: 10.1016/0378-1119(84)90235-X - 22.
Butt TR, Sternberg EJ, Gorman JA, Clark P, Hamer D, Rosenberg M, Crooke ST. Copper metallothionein of yeast, structure of the gene, and regulation of expression. Proceedings of the National Academy of Sciences of the United States of America. 1984; 81 :3332-3336 - 23.
Jensen LT, Howard WR, Strain JJ, Winge DR, Culotta VC. Enhanced effectiveness of copper ion buffering by CUP1 metallothionein compared withCRS5 metallothionein inSaccharomyces cerevisiae . The Journal of Biological Chemistry. 1996;271 :18514-18519. DOI: 10.1074/jbc.271.31.18514 - 24.
Ecker DJ, Butt TR, Sternberg EJ, Neeper MP, Debouck C, Gorman JA, Crooke ST. Yeast metallothionein function in metal ion detoxification. The Journal of Biological Chemistry. 1986; 261 :16895-168900 - 25.
Jeyaprakash A, Welch JW, Fogel S. Multicopy CUP1 plasmids enhance cadmium and copper resistance levels in yeast. Molecular & General Genetics. 1991;225 :363-368 - 26.
Winge DR, Nielson KB, Gray WR, Hamer DH. Yeast metallothionein. Sequence and metal-binding properties. The Journal of Biological Chemistry. 1985; 260 :14464-14470 - 27.
Culotta VC, Howard WR, Liu XF. CRS5 encodes a metallothionein-like protein in Saccharomyces cerevisiae . The Journal of Biological Chemistry. 1994;269 :25295-25302 - 28.
Pagani A, Villarreal L, Capdevila M, Atrian S. The Saccharomyces cerevisiae Crs5 Metallothionein metal-binding abilities and its role in the response to zinc overload. Molecular Microbiology. 2007;63 :256-269. DOI: 10.1111/j.1365-2958.2006.05510.x - 29.
Zhou J, Goldsbrough PB. Functional homologs of fungal metallothionein genes from Arabidopsis . Plant Cell. 1994;6 :875-884. DOI: 10.1105/tpc.6.6.875 - 30.
Guo WJ, Meetam M, Goldsbrough PB. Examining the specific contributions of individual Arabidopsis metallothioneins to copper distribution and metal tolerance. Plant Physiology. 2008;146 :1697-1706. DOI: 10.1104/pp.108.115782 - 31.
Mudalkar S, Golla R, Sengupta D, Ghatty S, Reddy AR. Molecular cloning and characterisation of metallothionein type 2a gene from Jatropha curcas L., a promising biofuel plant. Molecular Biology Reports. 2014;41 :113-124. DOI: 10.1007/s11033-013-2843-5 - 32.
Tomas M, Pagani MA, Andreo CS, Capdevila M, Atrian S, Bofill R. Sunflower metallothionein family characterisation. Study of the Zn(II)- and Cd(II)-binding abilities of the HaMT1 and HaMT2 isoforms. Journal of Inorganic Biochemistry. 2015; 48 :35-48. DOI: 10.1016/j.jinorgbio.2015.02.016 - 33.
Madejón P, Murillo JM, Marañón T, Cabrera F, Soriano MA. Trace element and nutrient accumulation in sunflower plants two years after the Aznalcóllar mine spill. The Science of the Total Environment. 2003; 307 :239-257. DOI: 10.1016/S0048-9697(02)00609-5 - 34.
Krämer U. Metal hyperaccumulation in plants. Annual Review of Plant Biology. 2010; 61 :517-534. DOI: 10.1146/annurev-arplant-042809-112156 - 35.
Roosens NH, Leplae R, Bernard C, Verbruggen N. Variations in plant metallothioneins: The heavy metal hyperaccumulator Thlaspi caerulescens as a study case. Planta. 2005;222 :716-729. DOI: 10.1007/s00425-005-0006-1 - 36.
van Hoof NA, Hassinen VH, Hakvoort HW, Ballintijn KF, Schat H, Verkleij JA, Ernst WH, Karenlampi SO, Tervahauta AI. Enhanced copper tolerance in Silene vulgaris (Moench) Garcke populations from copper mines is associated with increased transcript levels of a 2b-type metallothionein gene. Plant Physiology. 2001;126 :1519-1526. DOI: 10.1104/pp.126.4.1519 - 37.
Nevrtalova E, Baloun J, Hudzieczek V, Cegan R, Vyskot B, Dolezel J, Safar J, Milde D, Hobza R. Expression response of duplicated metallothionein 3 gene to copper stress in Silene vulgaris ecotypes. Protoplasma. 2014;251 :1427-1439. DOI: 10.1007/s00709-014-0644-x - 38.
Ansarypour Z, Shahpiri A. Heterologous expression of a rice metallothionein isoform (OsMTI-1b) in Saccharomyces cerevisiae enhances cadmium, hydrogen peroxide and ethanol tolerance. Brazilian Journal of Microbiology. 2017;48 (16):30354-30359. pii: S1517-8382. DOI: 10.1016/j.bjm.2016.10.024 - 39.
Yang Z, Wu Y, Li Y, Ling HQ, Chu C. OsMT1a, a type 1 metallothionein, plays the pivotal role in zinc homeostasis and drought tolerance in rice. Plant Molecular Biology. 2009; 70 :219-229. DOI: 10.1007/s11103-009-9466-1 - 40.
Jin S, Sun D, Wang J, Li Y, Wang X, Liu S. Expression of the rgMT gene, encoding for a rice metallothionein-like protein in Saccharomyces cerevisiae andArabidopsis thaliana . Journal of Genetics. 2014;93 :709-718 - 41.
Zhang M, Takano T, Liu S, Zhang X. Abiotic stress response in yeast and metal-binding ability of a type 2 metallothionein-like protein (PutMT2) from Puccinellia tenuiflora . Molecular Biology Reports. 2014;41 :5839-5849. DOI: 10.1007/s11033-014-3458-1 - 42.
Nishiuchi S, Liu S, Takano T. Isolation and characterization of a metallothionein-1 protein in Chloris virgata Swartz that enhances stress tolerances to oxidative, salinity and carbonate stress inSaccharomyces cerevisiae . Biotechnology Letters. 2007;29 :1301-1305. DOI: 10.1007/s10529-007-9396-4 - 43.
Yang J, Wang Y, Liu G, Yang C, Li C. Tamarix hispida metallothionein-like ThMT3, a reactive oxygen species scavenger, increases tolerance against Cd(2+), Zn(2+), Cu(2+), and NaCl in transgenic yeast. Molecular Biology Reports. 2011;38 :1567-1574. DOI: 10.1007/s11033-010-0265-1 - 44.
González-Guerrero M, Cano C, Azcón-Aguilar C, Ferrol N. GintMT1 encodes a functional metallothionein in Glomus intraradices that responds to oxidative stress. Mycorrhiza. 2007;17 :327-335. DOI: 10.1007/s00572-007-0108-7 - 45.
Ramesh G, Podila GK, Gay G, Marmeisse R, Reddy MS. Different patterns of regulation for the copper and cadmium metallothioneins of the ectomycorrhizal fungus Hebeloma cylindrosporum . Applied and Environmental Microbiology. 2009;75 :2266-2274. DOI: 10.1128/AEM.02142-08 - 46.
Bellion M, Courbot M, Jacob C, Guinet F, Blaudez D, Chalot M. Metal induction of a Paxillus involutus metallothionein and its heterologous expression inHebeloma cylindrosporum . The New Phytologist. 2007;174 :151-158. DOI: 10.1111/j.1469-8137.2007.01973.x - 47.
Silar P, Wegnez M. Expression of the Drosophila melanogaster metallothionein genes in yeast. FEBS Letters. 1990;269 :273-278. DOI: 10.1016/0014-5793(90)81172-K - 48.
Wang SH, Chang CY, Chen CF, Tam MF, Shih YH, Lin LY. Cloning of porcine neuron growth inhibitory factor (metallothionein III) cDNA and expression of the gene in Saccharomyces cerevisiae . Gene. 1997;203 :189-197. DOI: 10.1016/S0378-1119(97)00513-1 - 49.
Cismowski MJ, Huang PC. Purification of mammalian metallothionein from recombinant systems. Methods in Enzymology. 1991; 205 :312-319 - 50.
Cismowski MJ, Huang PC. Effect of cysteine replacements at positions 13 and 50 on metallothionein structure. Biochemistry. 1991; 30 :6626-6632 - 51.
Cismowski MJ, Narula SS, Armitage IM, Chernaik ML, Huang PC. Mutation of invariant cysteines of mammalian metallothionein alters metal binding capacity, cadmium resistance, and 113Cd NMR spectrum. The Journal of Biological Chemistry. 1991; 266 :24390-24397 - 52.
Wu Q, Li B, Wu F, Yang L, Li S, Li H, Wu D, Cui T, Tang D. High-level expression, efficient purification, and bioactivity of recombinant human metallothionein 3 (rhMT3) from methylotrophic yeast Pichia pastoris . Protein Expression and Purification. 2014;101 :121-126. DOI: 10.1016/j.pep.2014.06.009 - 53.
Capdevilaa M, Bofilla R, Palaciosa O, Atrianb S. State-of-the-art of metallothioneins at the beginning of the 21st century. Coordination Chemistry Reviews. 2012; 256 :46-62. DOI: 10.1016/j.ccr.2011.07.006 - 54.
Blindauer CA, Leszczyszyn OI. Metallothioneins: Unparalleled diversity in structures and functions for metal ion homeostasis and more. Natural Product Reports. 2010; 27 :720-741. DOI: 10.1039/b906685n - 55.
Bell SG, Vallee BL. The metallothionein/thionein system: An oxidoreductive metabolic zinc link. Chembiochem. 2009; 10 :55-62. DOI: 10.1002/cbic.200800511 - 56.
Vasak M. Metal removal and substitution in vertebrate and invertebrate metallothioneins. In: Riordan JF, Vallee BL, editors. Metallobiochemistry Part B, Metallothionein and Related Molecules. Vol. 205. 1st ed. San Diego: Academic Press; 1991. pp. 452-458. ISBN: 9780121821067 - 57.
Orihuela R, Monteiro F, Pagani A, Capdevila M, Atrian S. Evidence of native metal-S(2-)-metallothionein complexes confirmed by the analysis of Cup1 divalent-metal-ion binding properties. Chemistry. 2010; 16 :12363-12372. DOI: 10.1002/chem.201001125 - 58.
Shibasaki S, Ueda M. Bioadsorption strategies with yeast molecular display technology. Biocontrol Science. 2014; 19 :157-164. DOI: 10.4265/bio.19.157 - 59.
Li PS, Tao HC. Cell surface engineering of microorganisms towards adsorption of heavy metals. Critical Reviews in Microbiology. 2015; 41 :140-149. DOI: 10.3109/1040841X.2013.813898 - 60.
Cherf GM, Cochran JR. Applications of yeast surface display for protein engineering. Methods in Molecular Biology. 2015; 1319 :155-175. DOI: 10.1007/978-1-4939-2748-7_8 - 61.
Liu Z, Ho SH, Hasunuma T, Chang JS, Ren NQ, Kondo A. Recent advances in yeast cell-surface display technologies for waste biorefineries. Bioresource Technology. 2016; 215 :324-333. DOI: 10.1016/j.biortech.2016.03.132 - 62.
Ueda M. Establishment of cell surface engineering and its development. Bioscience, Biotechnology, and Biochemistry. 2016; 80 :1243-1253. DOI: 10.1080/09168451.2016.1153953 - 63.
Kuroda K, Ueda M. Generation of arming yeasts with active proteins. In: Mapelli V, editor. Yeast Metabolic Engineering: Methods and Protocols. Methods in Molecular Biology, 1st ed. Humana Press, Springer Science + Business Media, Springer New York Heidelberg Dordrecht London; 2014. pp. 137-157. DOI: 10.1007/978-1-4939-0563-8_8 - 64.
Kuroda K, Ueda M. Engineering of microorganisms towards recovery of rare metals. Applied Microbiology and Biotechnology. 2010; 87 :53-60. DOI: 10.1007/s00253-010-2581-8 - 65.
Brady D, Stoll AD, Starke L, Duncan JR. Chemical and enzymatic extraction of heavy metal binding polymers from isolated cell walls of Saccharomyces cerevisiae . Biotechnology and Bioengineering. 1994;44 :297-302. DOI: 10.1002/bit.260440307 - 66.
Kuroda K, Ueda M. Bioadsorption of cadmium ion by cell surface-engineered yeasts displaying metallothionein and hexa-His. Applied Microbiology and Biotechnology. 2003; 63 :182-186. DOI: 10.1007/s00253-003-1399-z - 67.
Kuroda K, Ueda M. Effective display of metallothionein tandem repeats on the bioadsorption of cadmium ion. Applied Microbiology and Biotechnology. 2006; 70 :458-463. DOI: 10.1007/s00253-005-0093-8 - 68.
Wei Q, Zhang H, Guo D, Ma S. Cell surface display of four types of Solanum nigrum metallothionein onSaccharomyces cerevisiae for biosorption of cadmium. Journal of Microbiology and Biotechnology. 2016;26 :846-853. DOI: 10.4014/jmb.1512.12041 - 69.
Ferraz P, Fidalgo F, Almeid A, Teixeira J. Phytostabilization of nickel by the zinc and cadmium hyperaccumulator Solanum nigrum L. Are metallothioneins involved?. Plant Physiology and Biochemistry. 2012;57 :254-260. DOI: 10.1016/j.plaphy.2012.05.025 - 70.
Krämer U. Phytoremediation: Novel approaches to cleaning up polluted soils. Current Opinion in Biotechnology. 2005; 16 :133-141. DOI: 10.1016/j.copbio.2005.02.006 - 71.
Dürr G, Strayle J, Plemper R, Elbs S, Klee SK, Catty P, Wolf DH, Rudolph HK. The medial-Golgi ion pump Pmr1 supplies the yeast secretory pathway with Ca2+ and Mn2+ required for glycosylation, sorting, and endoplasmic reticulum-associated protein degradation. Molecular Biology of the Cell. 1998; 9 :1149-1162. DOI: 10.1091/mbc.9.5.1149 - 72.
Lauer Júnior CM, Bonatto D, Mielniczki-Pereira AA, Schuch AZ, Dias JF, Yoneama ML, Pegas Henriques JA. The Pmr1 protein, the major yeast Ca2+-ATPase in the Golgi, regulates intracellular levels of the cadmium ion. FEMS Microbiology Letters. 285 :79-88. DOI: 10.1111/j.1574-6968.2008.01214.x - 73.
Geva P, Kahta R, Nakonechny F, Aronov S, Nisnevitch M. Increased copper bioremediation ability of new transgenic and adapted Saccharomyces cerevisiae strains. Environmental Science and Pollution Research International. 2016;23 :19613-19625. DOI: 10.1007/s11356-016-7157-4 - 74.
Küpper H, Götz B, Mijovilovich A, Küpper FC, Meyer-Klaucke W. Complexation and toxicity of copper in higher plants. I. Characterization of copper accumulation, speciation, and toxicity in Crassula helmsii as a new copper accumulator. Plant Physiology. 2009;151 :702-714. DOI: 10.1104/pp.109.139717 - 75.
Mijovilovich A, Leitenmaier B, Meyer-Klaucke W, Kroneck PMH, Goötz B, Küpper H. Complexation and toxicity of copper in higher plants. II. Different mechanisms for copper versus cadmium detoxification in the copper-sensitive cadmium/zinc hyperaccumulator Thlaspi caerulescens (Ganges ecotype). Plant Physiology. 2009;151 :715-731. DOI: 10.1104/pp.109.144675 - 76.
Zhang J, Zhang M, Tian S, Lu L, Shohag MJ, Yang X. Metallothionein 2 (SaMT2) from Sedum alfredii Hance confers increased Cd tolerance and accumulation in yeast and tobacco. PloS One. 2014;9 :e102750. DOI: 10.1371/journal.pone.0102750 - 77.
Beneš V, Hložková K, Matěnová M, Borovička J, Kotrba P. Accumulation of Ag and Cu in Amanita strobiliformis and characterization of its Cu and Ag uptake transporter genesAsCTR2 andAsCTR3 . Biometals. 2016;29 :249-264. DOI: 10.1007/s10534-016-9912-x - 78.
Hložková K, Matěnová M, Žáčková P, Strnad H, Hršelová H, Hroudová M, Kotrba P. Characterization of three distinct metallothionein genes of the Ag-hyperaccumulating ectomycorrhizal fungus Amanita strobiliformis . Fungal Biology. 2016;120 :358-369. DOI: 10.1016/j.funbio.2015.11.007 - 79.
Mercogliano CP, DeRosier DJ. Gold nanocluster formation using metallothionein: mass spectrometry and electron microscopy. Journal of Molecular Biology. 2006; 355 :211-223. DOI: 10.1016/j.jmb.2005.10.026 - 80.
Mercogliano CP, DeRosier DJ. Concatenated metallothionein as a clonable gold label for electron microscopy. Journal of Structural Biology. 2007; 160 :70-82. DOI: 10.1016/j.jsb.2007.06.010 - 81.
Fernández de Castro I, Sanz-Sánchez L, Risco C. Metallothioneins for correlative light and electron microscopy. Methods in Cell Biology. 2014; 124 :55-70. DOI: 10.1016/B978-0-12-801075-4.00003-3 - 82.
Morphew MK, O'Toole ET, Page CL, Pagratis M, Meehl J, Giddings T, Gardner JM, Ackerson C, Jaspersen SL, Winey M, Hoenger A, McIntosh JR. Metallothionein as a clonable tag for protein localization by electron microscopy of cells. Journal of Microscopy. 2015; 260 :20-29. DOI: 10.1111/jmi.12262 - 83.
Presta A, Stillman MJ. Incorporation of copper into the yeast Saccharomyces cerevisiae . Identification of Cu(I)—metallothionein in intact yeast cells. Journal of Inorganic Biochemistry. 1997;66 :231-240. DOI: 10.1016/S0162-0134(96)00216-4 - 84.
Nakayama K, Okabe M, Aoyagi K, Yamanoshita O, Okui T, Ohyama T, Kasai N. Visualization of yellowish-orange luminescence from cuprous metallothioneins in liver of Long-Evans Cinnamon rat. Biochimica et Biophysica Acta. 1996; 1289 :150-158 - 85.
McNulty M, Puljung M, Jefford G, Dubreuil RR. Evidence that a copper-metallothionein complex is responsible for fluorescence in acid-secreting cells of the Drosophila stomach. Cell and Tissue Research. 2001;304 :383-389. DOI: 10.1007/s004410100371 - 86.
Ni TW, Staicu LC, Nemeth RS, Schwartz CL, Crawford D, Seligman JD, Hunter WJ, Pilon-Smits EA, Ackerson CJ. Progress toward clonable inorganic nanoparticles. Nanoscale. 2015; 7 :17320-17327. DOI: 10.1039/c5nr04097c