Selective Cu2+ Binding, Redox Silencing, and Cytoprotective Effects of the Small Heat Shock Proteins αA- and αB-Crystallin

Ahmad, Md. Faiz; Singh, Dalbir; Taiyab, Aftab; Ramakrishna, T.; Raman, Bakthisaran; Rao, Ch. Mohan

doi:10.1016/j.jmb.2008.07.068

Cited by 75 publications

(79 citation statements)

References 56 publications

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“…The protein solutions were degassed for 10 min before use. To stabilize Cu(II) in buffered solution and to minimize nonspecific binding of Cu(II) in the titration experiment, we used Cu(Gly) 2 as a weak chelator (26). The glycine solution was prepared by dissolving glycine in the corresponding buffer after dialysis.…”

Section: Methodsmentioning

confidence: 99%

“…Intriguingly, divalent metal ions like Cu(II) and Zn(II) can act as modulators of this chaperone property (23)(24)(25). It was shown recently that ␣B can coordinate Cu(II) with a picomolar affinity, whereas the interaction with other divalent metal ions is significantly weaker (26). Cu(II) affects the secondary structure and oligomeric size of ␣B (26,27).…”

mentioning

confidence: 99%

“…It was shown recently that ␣B can coordinate Cu(II) with a picomolar affinity, whereas the interaction with other divalent metal ions is significantly weaker (26). Cu(II) affects the secondary structure and oligomeric size of ␣B (26,27). Furthermore, ␣B is able to reduce Cu(II)-mediated formation of reactive oxygen species, thereby conferring cytoprotection to cells under conditions of oxidative stress (26).…”

mentioning

confidence: 99%

“…Cu(II) affects the secondary structure and oligomeric size of ␣B (26,27). Furthermore, ␣B is able to reduce Cu(II)-mediated formation of reactive oxygen species, thereby conferring cytoprotection to cells under conditions of oxidative stress (26).…”

mentioning

confidence: 99%

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Structural and Mechanistic Implications of Metal Binding in the Small Heat-shock Protein αB-crystallin

Mainz

Bardiaux

Kuppler

et al. 2012

Journal of Biological Chemistry

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Background: ␣B-crystallin is an ATP-independent chaperone that prevents irreversible protein aggregation. Results: Cu(II) binds to the core domain of ␣B-crystallin, induces increased dynamics at the dimer interface, and thus modulates the anti-aggregation properties of the chaperone. Conclusion:The small heat-shock protein ␣B-crystallin is a metal-regulated chaperone. Significance:The results open new perspectives in the field of protein homeostasis and oxidative stress resistance.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Structural and Mechanistic Implications of Metal Binding in the Small Heat-shock Protein αB-crystallin

Mainz

Bardiaux

Kuppler

et al. 2012

Journal of Biological Chemistry

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“…Cu 2+ binding induces structural changes and increase in the hydrodynamic radii of α-crystallins. The Cu 2+ -sequestering (redox-silencing) property of α-crystallins confers cytoprotection and helps in understanding their protective role in neurodegenerative diseases and cataract (Ahmad et al, 2008).…”

Section: Hsp60 Familymentioning

confidence: 99%

An overview on the small heat shock proteins

Mahmood¹,

Safdar²,

Abbasi³

et al. 2010

Afr. J. Biotechnol.

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In the last 25 years, a huge amount of literature has been accumulated describing the cell's response to different kinds of environmental stress conditions, such as high temperatures, altered pH, exposure of the cell to toxins, starvation, oxygen, and water deprivation, among others. Heat shock proteins (HSPs) are one of the main expressed products of the cell in response to stresses. HSPs can be classified into six structurally conserved classes according to their molecular weight namely, HSP100, HSP90, HSP70, HSP60, small heat shock proteins (sHSPs) and ubiquitin (8.5 kDa). In eukaryotes, different heat shock genes are expressed uncoordinatedly, whereas in prokaryote, heat shock genes form a regulon and appear simultaneously. sHSPs are associated with nuclei, cytoskeleton and membranes. They bind partially to denatured proteins, preventing irreversible protein aggregation during stress. In animals, only one sHSP gene has been located in yeast cells, ten in mammalian, two in birds and four genes have been found in Drosophila. However, in plants more than 20 sHSPs have been reported and they can be divided into 6 classes, of which, 3 classes (CI, CII and CIII) are in the cytosole or in the nucleus and the other three (CIV, CV and CVI) in the plastids, endoplasmic reticulum and mitochondria. Mitochondrial and chloroplast sHSPs protect electron transport chain. During development in animals, sHSP genes are normally regulated at late neurula and early tailbud stage and in plants during pollen development, seed maturation, seed imbibition and germination. Transcriptional regulation of sHSPs depends on particular activation of heat shock factors (HSF) which recognize the highly conserved heat-shock elements (HSEs). After the heat stress has been released, the sHSPs are quite stable, suggesting that sHSPs may be important for recovery as well.

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A novel function of Mycobacterium tuberculosis chaperonin paralog GroEL1 in copper homeostasis

et al. 2020

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Among the two GroEL paralogs in Mycobacterium tuberculosis, GroEL1 and GroEL2, GroEL1 has a characteristic histidine-rich C terminus. Since histidine richness is likely to be involved in metal binding, we attempted to decipher the role of GroEL1 in chelating metals and the consequence on M. tuberculosis physiology. Isothermal titration calorimetry showed that GroEL1 binds copper and other metals. Mycobacterial viability assay, redox balance, and DNA protection assay concluded that GroEL1 protects from copper stress in vitro. Solution X-ray scattering and constrained modeling of GroEL1 À/+ copper ions showed reorientation of the apical domain as seen in functional assembly. We conclude that the duplication of chaperonin genes in M. tuberculosis might have led to their evolutionary divergence and consequent functional divergence of chaperonins.

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Selective Cu2+ Binding, Redox Silencing, and Cytoprotective Effects of the Small Heat Shock Proteins αA- and αB-Crystallin

Cited by 75 publications

References 56 publications

Structural and Mechanistic Implications of Metal Binding in the Small Heat-shock Protein αB-crystallin

Structural and Mechanistic Implications of Metal Binding in the Small Heat-shock Protein αB-crystallin

An overview on the small heat shock proteins

A novel function of Mycobacterium tuberculosis chaperonin paralog GroEL1 in copper homeostasis

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