Subunit Mobility and the Chaperone Activity of Recombinant aB-Crystallin

Krushelnitsky, Alexey; Mukhametshina, N. E.; Gogolev, Yu. V.; Tarasova, N. B.; Faizullin, Dzhigangir A.; Zinkevich, Tatiana; Гнездилов, О. И.; Fedotov,

doi:10.2174/1874091x00802010116

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…Under conditions favorable for αB crystallin-tubulin mixed complexes, the pool of tubulin subunits decreased and assembly of microtubules was inhibited. The dynamic model for regulation of tubulin assembly by αB crystallin is consistent with published reports on the importance of dynamic subunit exchange and functional activity of αB crystallin [14] , [51] , [52] .…”

Section: Discussionsupporting

confidence: 88%

“…Similarly the dynamic spherical complexes of αB crystallin, the archetype for sHSP, vary greatly in size, with the median size reported to be approximately 24 subunits [10] , [12] . As with other dynamic molecular equilibria, the assembly of the αB crystallin complex is regulated by cofactors including Ca 2+ , ATP, and arginine-HCl [12] , [13] , [14] . The αB crystallin subunit consists of non-conserved N- and C-terminal domains and a highly conserved α crystallin core domain.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Subunit Exchange and the Regulation of Microtubule Assembly by the Stress Response Protein Human αB Crystallin

Houck

Clark

2010

PLoS ONE

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BackgroundThe small heat shock protein (sHSP), human αB crystallin, forms large, polydisperse complexes that modulate the tubulin-microtubule equilibrium using a dynamic mechanism that is poorly understood. The interactive sequences in αB crystallin for tubulin are surface exposed, and correspond to interactive sites for the formation of αB crystallin complexes.Methodology/Principal FindingsThere is sequence homology between tubulin and the interactive domains in the β8-strand of the core domain and the C-terminal extension of αB crystallin. This study investigated the hypothesis that the formation of tubulin and αB crystallin quaternary structures was regulated through common interactive domains that alter the dynamics of their assembly. Size exclusion chromatography (SEC), SDS-PAGE, microtubule assembly assays, aggregation assays, multiple sequence alignment, and molecular modeling characterized the dynamic response of tubulin assembly to increasing concentrations of αB crystallin. Low molar ratios of αB crystallin∶tubulin were favorable for microtubule assembly and high molar ratios of αB crystallin∶tubulin were unfavorable for microtubule assembly. Interactions between αB crystallin and unassembled tubulin were observed using SEC and SDS-PAGE.Conclusions/SignificanceSubunits of αB crystallin that exchange dynamically with the αB crystallin complex can interact with tubulin subunits to regulate the equilibrium between tubulin and microtubules.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Dynamic Subunit Exchange and the Regulation of Microtubule Assembly by the Stress Response Protein Human αB Crystallin

Houck

Clark

2010

PLoS ONE

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“…We assume that the addition of α-crystallin (α) to the protein substrate (UV-irradiated Ph b ; P) results in the relatively fast formation of the (α·P)* complex (complex I). It is well-known that the quaternary structure of α-crystallin is highly dynamic, with subunits capable of freely and rapidly exchanging between oligomers. ,− Because of the high mobility of α-crystallin, particle complex I is very unstable and undergoes structural rearrangement that ultimately results in the formation of a complex containing dissociated forms of α-crystallin, α i , and dissociated forms of protein substrate, p (this complex, α i · p , is designated as complex II), and water-soluble α-crystallin-unfolded target protein high-molecular weight complex α·P (complex III). The rearrangement of the (α·P)* complex may involve the following stages: splitting out of the α-crystallin subunit from the oligomer, disassembly of the protein substrate (primary aggregates of UV-irradiated Ph b , P) as a result of interaction with the α-crystallin matrix, binding of the protein substrate to the dissociated forms of α-crystallin, and reassociation of α i · p particles into high-molecular weight complexes containing entrapped substrate (α·P, complex III).…”

Section: Discussionmentioning

confidence: 99%

Does the Crowded Cell-like Environment Reduce the Chaperone-like Activity of α-Crystallin?

et al. 2011

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The effect of crowding on the chaperone-like activity of α-crystallin has been studied using aggregation of UV-irradiated glycogen phosphorylase b (Phb) from rabbit skeletal muscle as an aggregation test system. The merit of this test system is the possibility of testing agents that directly affect the stage of aggregation of the protein molecules. It was shown that the solution of Phb denatured by UV contained aggregates with a hydrodynamic radius of 10.4 nm. These aggregates are relatively stable at 20 °C; however, they reveal a tendency to stick further in the presence of crowding agents. The study of the effect of α-crystallin on the aggregation of UV-irradiated Phb in the presence of the crowding agents by dynamic light scattering at 37 °C showed that under crowding conditions the antiaggregation ability of α-crystallin was weakened. On the basis of the analytical ultracentrifugation, size-exclusion chromatography, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis data, the scheme of interaction of UV-irradiated Phb and α-crystallin has been proposed. It is assumed that chaperone-target protein complexes of two types are formed, namely, the complexes of dissociated forms of α-crystallin with a protein substrate and high-mass α-crystallin-denatured protein complexes. The complexes of the first type reveal a weak propensity to aggregate even under crowding conditions. The complexes of the second type are characterized by the lower rate of aggregation in comparison with that of original UV-irradiated Phb. However, crowding stimulates the rate of aggregation of these complexes, resulting in the above-mentioned decrease in the chaperone-like activity of α-crystallin.

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“…Previous study indicated that formation of HMW species by α-Cry affects the dynamic structure of this protein and decreases the rate of its subunit exchange [61]. Also the important role of subunit mobility in the chaperoning mechanism of αB-Cry has been already documented [62]. The enhancement of chaperone activity of this protein after moderate PON modification (Fig.…”

Section: ►Fig 7 To Be Inserted Here◄mentioning

confidence: 74%

Evaluation of structure, chaperone-like activity and protective ability of peroxynitrite modified human α-Crystallin subunits against copper-mediated ascorbic acid oxidation

Ghahramani

Yousefi

Khoshaman

et al. 2016

International Journal of Biological Macromolecules

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The copper-catalyzed oxidation of ascorbic acid (ASA) to dehydroascorbate (DHA) and hydrogen peroxide plays a central role in pathology of cataract diseases during ageing and in diabetic patients. In the current study, the structural feature, chaperone-like activity and protective ability of peroxynitrite (PON) modified αA- and αB-Crystallin (Cry) against copper-mediated ASA oxidation were studied using different spectroscopic measurements and gel mobility shift assay. Upon PON modification, additional to protein structural alteration, the contents of nitrotyrosine, nitrotryptophan, dityrosine and carbonyl groups were significantly increased. Moreover, αB-Cry demonstrates significantly larger capacity for PON modification than αA-Cry. Also, based on the extent of PON modification, these proteins may display an improved chaperone-like activity and enhanced protective ability against copper-mediated ASA oxidation. In the presence of copper ions, chaperone-like activity of both native and PON-modified α-Cry subunits were appreciably improved. Additionally, binding of copper ions to native and PON-modified proteins results in the significant reduction of their solvent exposed hydrophobic patches. Overall, the increase in chaperone-like activity/ASA protective ability of PON-modified α-Cry and additional enhancement of its chaperoning action with copper ions appear to be an important defense mechanism offered by this protein.

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Subunit Mobility and the Chaperone Activity of Recombinant aB-Crystallin

Cited by 4 publications

References 23 publications

Dynamic Subunit Exchange and the Regulation of Microtubule Assembly by the Stress Response Protein Human αB Crystallin

Dynamic Subunit Exchange and the Regulation of Microtubule Assembly by the Stress Response Protein Human αB Crystallin

Does the Crowded Cell-like Environment Reduce the Chaperone-like Activity of α-Crystallin?

Evaluation of structure, chaperone-like activity and protective ability of peroxynitrite modified human α-Crystallin subunits against copper-mediated ascorbic acid oxidation

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