The pivotal role of the beta 7 strand in the intersubunit contacts of different human small heat shock proteins

Human alpha B-crystallin and small heat shock proteins HspB6 and HspB8 were mutated so that all endogenous Cys residues were replaced by Ser and the single Cys residue was inserted in a position homologous to that of Cys137 of human HspB1, i.e. in a position presumably located in the central part of...

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Bibliographic Details
Published in:Cell stress & chaperones 2010-07, Vol.15 (4), p.365
Main Authors: Mymrikov, Evgeny V, Bukach, Olesya V, Seit-Nebi, Alim S, Gusev, Nikolai B
Format: Article
Language:English
Subjects:
alpha-Crystallin B Chain - chemistry
Amino Acid Substitution
Circular Dichroism
Cysteine - chemistry
Heat-Shock Proteins - chemistry
Heat-Shock Proteins, Small - chemistry
Heat-Shock Proteins, Small - genetics
Heat-Shock Proteins, Small - metabolism
HSP20 Heat-Shock Proteins - chemistry
HSP27 Heat-Shock Proteins - chemistry
Humans
Molecular Chaperones
Protein Serine-Threonine Kinases - chemistry
Protein Structure, Quaternary
Protein Structure, Secondary
Protein Structure, Tertiary
Recombinant Proteins - chemistry
Recombinant Proteins - genetics
Recombinant Proteins - metabolism
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Summary:Human alpha B-crystallin and small heat shock proteins HspB6 and HspB8 were mutated so that all endogenous Cys residues were replaced by Ser and the single Cys residue was inserted in a position homologous to that of Cys137 of human HspB1, i.e. in a position presumably located in the central part of beta 7 strand of the alpha-crystallin domain. The secondary, tertiary, and quaternary structures of thus obtained Cys-mutants as well as their chaperone-like activity were similar to those of their wild-type counterparts. Mild oxidation of Cys-mutants leads to formation of disulfide bond crosslinking neighboring monomers thus indicating participation of the beta 7 strand in intersubunit interaction. Oxidation weakly affects the secondary and tertiary structure, does not affect the quaternary structure of alpha B-crystallin and HspB6, and shifts equilibrium between monomer and dimer of HspB8 towards dimer formation. It is concluded that the beta 7 strand participates in the intersubunit interaction of four human small heat shock proteins (alpha B-crystallin, HspB1, HspB6, HspB8) having different structure of beta2 strand of alpha-crystallin domain and different length and composition of variable N- and C-terminal tails.
ISSN:1466-1268
DOI:10.1007/s12192-009-0151-8