Evidence for a Dynamic Structure of Human Neuronal Growth Inhibitory Factor and for Major Rearrangements of Its Metal−Thiolate Clusters

Faller, Peter; Hasler, Daniel W.; Zerbe, Oliver; Klauser, Stephan; Winge, Dennis R.; Vašák, Milan

doi:10.1021/bi990489c

Cited by 93 publications

(131 citation statements)

References 43 publications

Supporting

Mentioning

118

Contrasting

Order By: Relevance

“…NMR techniques have not detected domain interactions in solutions of MT. Yet, a comparison between the properties of MT-3 and those of its individual clusters (34,35) revealed that they mutually stabilize each other (36). In accord with these studies, either 113 Cd or 1 H NMR lines of the isolated ␤-domain of MT-2 are broad.…”

Section: Discussionmentioning

confidence: 62%

Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Jiang

Vašák

Vallée

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

129

111

View full text Add to dashboard Cite

The ␣-and ␤-polypeptides of human metallothionein (isoform 2), obtained by chemical synthesis, were converted into their respective zinc͞thiolate clusters, and each domain was investigated separately. Proton titration data for the N-terminal ␤-domain fit a simple model with three ionizations of the same apparent pK a value of 4.9 and a collective binding constant for zinc of 5 ؋ 10 ؊12 M at pH 7.0. The zinc cluster in the C-terminal ␣-domain is more stable than that in the ␤-domain. Its pH titration is also more complex, indicating at least two classes of zinc sites with different affinities. The whole molecule is stabilized with regard to the individual domains. Chemical modification implicates lysine side chains in both the stabilization of the ␤-domain cluster and the mutual stabilization of the domains in the whole molecule. The two zinc clusters also differ in the reactivity of their cysteine sulfurs and their potential to donate zinc to an acceptor molecule dependent on its type and characteristics. The isolated ␤-domain cluster reacts faster with Ellman's reagent and is a better zinc donor toward zinc-depleted sorbitol dehydrogenase than is the isolated ␣-domain cluster, whereas the reverse is observed when a chelating agent is the zinc acceptor. Thus, although each cluster assembles independently of the other, the cumulative properties of the individual domains do not suffice to describe metallothionein either structurally or functionally. The two-domain structure of the whole molecule is important for its interaction with ligands and for control of its reactivity and overall conformation.

show abstract

Section: Discussionmentioning

confidence: 62%

Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Jiang

Vašák

Vallée

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

129

111

View full text Add to dashboard Cite

show abstract

“…Expression in Escherichia coli strain BL21(DE3)pLys and purification was performed as described previously (31). The metal-free protein (apoprotein) was generated with the method of Vasak (32).…”

Section: Methodsmentioning

confidence: 99%

Redox Silencing of Copper in Metal-linked Neurodegenerative Disorders

Meloni

Faller

Vašák

2007

Journal of Biological Chemistry

Self Cite

120

159

View full text Add to dashboard Cite

Dysregulation of copper and zinc homeostasis in the brain plays a critical role in Alzheimer disease (AD). Copper binding to amyloid-␤ peptide (A␤) is linked with the neurotoxicity of A␤and free radical damage. Metallothionein-3 (MT-3) is a small cysteine-and metal-rich protein expressed in the brain and found down-regulated in AD. This protein occurs intra-and extracellularly, and it plays an important role in the metabolism of zinc and copper. In cell cultures Zn 7 MT-3, by an unknown mechanism, protects neurons from the toxicity of A␤. We have, therefore, used a range of complementary spectroscopic and biochemical methods to characterize the interaction of Zn 7 MT-3 with free Cu 2؉ ions. We show that Zn 7 MT-3 scavenges free Cu Essential transition metals like copper and zinc play a critical role in neurobiology. The homeostasis of both metals is tightly regulated and essential for brain physiology (1). In vitro evidence suggests that in physiological conditions micromolar concentrations of zinc and copper are actively released from neurons during neurotransmission processes into pre-and postsynaptic clefts. However, at present it is not known whether the released copper is present in a chemically exchangeable form (2). Dysregulated metal metabolism (zinc and copper) occurs in neurodegenerative disorders such as Alzheimer (3, 4), Parkinson (5), and prion (6) diseases. In these diseases increased extracellular copper concentrations and free-radical production have been found. There is now direct evidence that copper is bound to amyloid-␤ peptide (A␤) 2 in senile plaque of Alzheimer disease (AD) (7). Copper is also linked with the neurotoxicity of A␤ and free radical damage (8).Because of its redox-active nature (Cu ϩ /Cu 2ϩ ), its reactivity with molecular oxygen (O 2 ) generates the reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, and hydroxyl radicals (9, 10). The redox cycling of copper requires its reduction by biological components, including ascorbate, which actively accumulates in the brain at concentrations between 0.5 and 10 mM (11). Hence, copper chelation and its redox-silencing may represent critical events in preventing the progression of neurodegenerative diseases. In recent years a metal chelation therapy has emerged as a promising tool to attenuate abnormal metal-protein interactions that lead to increased free-radical toxicity (10).The natural metal chelator metallothionein-3 (MT-3), also known as the growth inhibitory factor, is a small non-inducible cysteine-and metal-rich protein mainly expressed in the brain. In the brain its expression was found in zinc-enriched neurons. Like other mammalian metallothioneins (MTs), MT-3 binds with a high affinity essential monovalent and divalent d 10 metal ions Cu(I) and Zn(II). Recently, the interaction of Zn 7 MT-3 with the small-GTPase Rab3a, which is strictly linked to the exo-endocytotic cycle of synaptic vesicles, has been demonstrated. It has been suggested that Zn 7 MT-3 actively participates in synaptic cycle of zinc vesicles...

show abstract

“…These features are typical of Cu(II) coordination by three nitrogen and one oxygen ligands (3N1O) 18,19 . Since MT-3 is devoid of aromatic amino acids, the metalinduced shoulder in the absorption spectrum of Zn 7 MT-3 at about 235 nm originates from the CysS-Zn(II) charge-transfer transitions 11 . Addition of Zn 7 MT-3 to Aβ 1-40 -Cu(II) revealed new absorption features above 250 nm characteristic of the CysS-Cu(I) charge-transfer transitions 21 .…”

Section: Zn 7 Mt-3 Removes Copper From Soluble Aβ 1-40 -Cu(ii)mentioning

confidence: 99%

“…The structural studies revealed that Zn 7 MT-3, like other mammalian metallothioneins, contains two metalthiolate clusters localized in independent protein domains, i.e., the Zn 3 (CysS) 9 cluster in the Nterminal β-domain and the Zn 4 (CysS) 11 cluster in the C-termial α-domain [10][11][12] . In the brain, Zn 7 MT-3 is localized in neurons, astrocytes and in the extracellular space in comparable amounts 13 and was found down-regulated in AD 14 .…”

mentioning

confidence: 99%

“…Zn 7 MT-3 shows a biphasic CD profile with strong CD bands at (+)247 and (-)228 nm, and a crossover point at 239 nm. These CD features originate from an excitonic splitting of the first CysS-Zn(II) charge transfer transition at 235 nm 11 . By marked contrast, the CD spectrum of Aβ -Cu (II) shows only a small contribution to that of Aβ in the spectral region between 230-260 nm.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Metal swap between Zn7-metallothionein-3 and amyloid-β–Cu protects against amyloid-β toxicity

et al. 2008

Self Cite

View full text Add to dashboard Cite

Metal swap between Zn7metallothionein-3 and amyloid-β-Cu protects against amyloid-β toxicity Meloni, G; Sonois, V; Delaine, T; Guilloreau , L; Gillet, A; Teissie, J; Faller, P; Vasak, M Meloni, G; Sonois, V; Delaine, T; Guilloreau , L; Gillet, A; Teissie, J; Faller, P; Vasak, M (2008). Metal swap between Zn7metallothionein-3 and amyloid-β-Cu protects against amyloid-β toxicity. Nature Chemical Biology, 4 Metal swap between Zn7metallothionein-3 and amyloid-β-Cu protects against amyloid-β toxicity Abstract Aberrant interactions of copper and zinc ions with the amyloid-β peptide (Aβ) potentiate Alzheimer disease (AD) by participating in the aggregation process of Aβ and in thegeneration of reactive oxygen species (ROS). The ROS production and the neurotoxicity of Aβ are associated with copper binding. Metallothionein-3 (Zn7MT-3), an intra-andextracellularly occurring metalloprotein, is highly expressed in the brain and down-regulated in AD. This protein protects, by an unknown mechanism, cultured neurons from the toxicity of Aβ. Herein, we show that a metal swap between Zn7MT-3 and soluble and aggregated Aβ1-40-Cu(II) abolishes the ROS production and the related cellular toxicity. In this process, copper is reduced by the protein thiolates forming Cu(I)4Zn4MT-3 in which an air stable Cu(I)4-thiolate cluster and two disulfide bonds are present. The discovered protective effect of Zn7MT-3 from the copper-mediated Aβ1-40 toxicity may lead to newtherapeutic strategies in treating AD.Metal swap between Zn 7 metallothionein-3 and amyloid-β-Cu protects against amyloid-β toxicity residue Aβ peptide, a proteolytic fragment generated from the amyloid precursor protein (APP)by β-and γ-secretases 1 . There is significant evidence indicating that the Aβ peptides can interact with metal ions such as Zn(II) and Cu(II), thereby participating in their aggregation and in the production of ROS 1, 2 . Whereas the copper-induced Aβ aggregation is related to the ROS production and neurotoxicity 3 , the zinc-induced Aβ aggregation is considered to be neuroprotective 4 . The ROS are generated by Aβ-Cu(II) through the redox cycling of copper which requires its reduction by biological components such as ascorbate (1), glutathione (2), dopamine (3), and cholesterol (4) 5,6 . A dysregulation of metal ion homeostasis, as occurs in AD, may foster an environment that promotes such degenerative conditions. The modulation of brain metal ion homeostasis, the reduction of aberrant metal-protein interactions by MPAC (metal-

show abstract

Evidence for a Dynamic Structure of Human Neuronal Growth Inhibitory Factor and for Major Rearrangements of Its Metal−Thiolate Clusters

Cited by 93 publications

References 43 publications

Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Redox Silencing of Copper in Metal-linked Neurodegenerative Disorders

Metal swap between Zn7-metallothionein-3 and amyloid-β–Cu protects against amyloid-β toxicity

Contact Info

Product

Resources

About