(Mercury)18-metallothionein

Cai, Wuhua; Stillman, Martin J.

doi:10.1021/ja00231a045

Cited by 36 publications

(17 citation statements)

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“…We can only postulate that each a domain is also somewhat discrete from the other two-domains when binding 3 As 3+ but upon coordinating the 10th and 11th As 3+ the individuality of each domain structure collapses, leaving a single globular structure, which may resemble that calculated for the apo-aaahMT [56]. A similar proposal was suggested to account for the very strong CD spectrum of Hg 18 -MT [57,58]. It was suggested that all 20 cysteines in rabbit liver baMT were involved in a single structure when binding Hg 2+ ions.…”

Section: Interdomain Metalationmentioning

confidence: 79%

Arsenic-metalation of triple-domain human metallothioneins: Support for the evolutionary advantage and interdomain metalation of multiple-metal-binding domains

Ngu

Lee

Pinter

et al. 2010

Journal of Inorganic Biochemistry

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Section: Interdomain Metalationmentioning

confidence: 79%

Arsenic-metalation of triple-domain human metallothioneins: Support for the evolutionary advantage and interdomain metalation of multiple-metal-binding domains

Ngu

Lee

Pinter

et al. 2010

Journal of Inorganic Biochemistry

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“…At low temperatures the kinetic product may be long lived and its presence may dominate subsequent reactions. For metallothionein, different cluster structures may be exhibited by the kinetic and thermodynamic product [13,34,351. Fig.…”

Section: Cu' Binding To Zn-metallothioneinmentioning

confidence: 99%

“…In addition to the M,-metallothionein species, mammalian metallothionein species containing up to 1 2 and, more recently, up to 18 metal iondprotein molecule have been made, in which distinct and ordered metal-thiolate structures are maintained or newly formed [12][13][14][15][24][25][26][27]. During formation of these novel complexes, the possibility arises that two or more metals, each with a different coordination geometry, can coexist within the same binding site.…”

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confidence: 99%

Copper Binding to Rabbit Liver Metallothionein

Presta

Green

Żelazowski

et al. 1995

European Journal of Biochemistry

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Circular dichroism and ultraviolet absorption spectral data have been used to probe the binding mechanism for formation and the structure of the copper(1)-thiolate binding clusters in rabbit liver metallothiionein during addition of Cu' to aqueous solutions of Zn,-metallothionein 2 and Cd,Zn,-metallothionein 2. Mammalian metallothionein binds metals in two binding sites, namely the a and P domains. Spectral data which probe the distribution of Cu(1) between the two binding domains clearly show that both the site of binding (a or p), and the structures of the specific metal-thiolate clusters formed, are dependent on temperature and on the nature of the starting protein (either Zn,-metallothionein or Cd,Zn,-metallothionein). CD spectra acquired during the addition of Cu' to Zn,-metallothionein show that Cu' replace the bound Zn(I1) in a domain-distributed manner with complete removal of the Zn(I1) after addition of 12 Cu'. Spectral and metal analyses prove that a series of Cu(1)-metallothionein species are formed by a non-cooperative metal-binding mechanism with a continuum of Cu(1) :metallothionein stoichionietries. Observation of a series of spectral saturation points signal the formation of distinct optically active Cu(1)-thiolate structures for the Cu,Zn,-metallothionein, Cu,,-metallothionein, and the Cu,,-metallothiionein species. These data very clearly show that for Cu(1) binding to Zn,-metallothionein, there are sleveral key Cu(1):metallothionein stoichiometric ratios, and not just the single value of 12. The CD spectra up to the Cu,,-metallothionein species are defined by bands located at 255(+) nm and 280(--) nm. Interpretation of the changes in the CD and ultraviolet absorption spectral data recorded between 3°C and 52°C as Cu' is added to Zn-metallothionein show that copper-thiolate cluster formation is strongly temperature dependent. These changes in spectral properties are interpreted in terms of kinetic versus thermodynamic control of the metal-binding pathways as Cu' binds to the protein. At low temperatures (3 "C and 10OC) the spectral data indicate a kinetically controlled mechanism whereby an activation barrier inhibits formation of ordered copper-thiolate structures until formation of Cu,,-metallothionein. At higher temperatures (>3OoC) the activation barrier is overcome, allowing formation of new Cu(1)-thiolate clusters with unique spectral properties, especially at the Cu,Zn,-metallothionein point. The CD spectra also show that a Cu,,-metallothionein species with a well-defined, three-dimensional structure forms at all temperatures, characterized by a band near 335 nm, indicating the presence of digonal Cu(1). Complicated CD spectral changes are observed when Cu' is added to Cd,Zn,-metallothionein. The spectral data are interpreted in terms of domain-distributed binding followed by rearrangement to form the domain-specific product. In the Cu,Cd,-metallothionein species, the Cu' are ultimately bound specifically to the p domain of the protein. This complex is characterised by the CD spectrum o...

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“…MTs are a family of cysteine-rich, metal-binding proteins that bind soft metals like mercury with a particularly high affinity [21,22,23]. Hg 2+ has been shown to have higher affinity for MTs than other Hg-species [24,25]. …”

Section: Introductionmentioning

confidence: 99%

A Simple Metallothionein-Based Biosensor for Enhanced Detection of Arsenic and Mercury

2017

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Metallothioneins (MTs) are a family of cysteine-rich proteins whose biological roles include the regulation of essential metal ions and protection against the harmful effects of toxic metals. Due to its high affinity for many toxic, soft metals, recombinant human MT isoform 1a was incorporated into an electrochemical-based biosensor for the detection of As3+ and Hg2+. A simple design was chosen to maximize its potential in environmental monitoring and MT was physically adsorbed onto paper discs placed on screen-printed carbon electrodes (SPCEs). This system was tested with concentrations of arsenic and mercury typical of contaminated water sources ranging from 5 to 1000 ppb. The analytical performance of the MT-adsorbed paper discs on SPCEs demonstrated a greater than three-fold signal enhancement and a lower detection limit compared to blank SPCEs, 13 ppb for As3+ and 45 ppb for Hg2+. While not being as low as some of the recommended drinking water limits, the sensitivity of the simple MT-biosensor would be potentially useful in monitoring of areas of concern with a known contamination problem. This paper describes the ability of the metal binding protein metallothionein to enhance the effectiveness of a simple, low-cost electrochemical sensor.

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(Mercury)18-metallothionein

Cited by 36 publications

References 1 publication

Arsenic-metalation of triple-domain human metallothioneins: Support for the evolutionary advantage and interdomain metalation of multiple-metal-binding domains

Arsenic-metalation of triple-domain human metallothioneins: Support for the evolutionary advantage and interdomain metalation of multiple-metal-binding domains

Copper Binding to Rabbit Liver Metallothionein

A Simple Metallothionein-Based Biosensor for Enhanced Detection of Arsenic and Mercury

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