Structure and properties of G84R and L99M mutants of human small heat shock protein HspB1 correlating with motor neuropathy.
Some properties of G84R and L99M mutants of HspB1 associated with peripheral distal neuropathies were investigated. Homooligomers formed by these mutants are larger than those of the wild type HspB1. Large oligomers of G84R and L99M mutants have compromised stability and tend to dissociate at low protein concentration. G84R and L99M mutations promote phosphorylation-dependent dissociation of HspB1 oligomers without affecting kinetics of HspB1 phosphorylation by MAPKAP2 kinase. Both mutants weakly interact with HspB6 forming small heterooligomers and being unable to form large heterooligomers characteristic for the wild type HspB1. G84R and L99M mutants possess lower chaperone-like activity than the wild type HspB1 with several model substrates. We suggest that G84R mutation affects mobility and accessibility of the N-terminal domain thus modifying interdimer contacts in HspB1 oligomers. The L99M mutation is located within the hydrophobic core of the α-crystallin domain close to the key R140 residue, and could affect the dimer stability.
Department of Biochemistry, School of Biology, Moscow State University, Moscow 119991, Russian Federation.
Victoria V
VV
Nefedova
Maria V
MV
Sudnitsyna
Sergei V
SV
Strelkov
Nikolai B
NB
Gusev
D000595:Amino Acid Sequence; D019281:Dimerization; D050886:HSP20 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics; D055551:HSP27 Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics*; D006360:Heat-Shock Proteins; D006801:Humans; D018832:Molecular Chaperones / Q000737:chemistry; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000378:metabolism*; D009154:Mutation; D009422:Nervous System Diseases / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D038201:alpha-Crystallins / Q000737:chemistry
D050886:HSP20 Heat-Shock Proteins; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; C494382:HSPB6 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D038201:alpha-Crystallins
Chaperone-like activity; Congenital diseases; Heterooligomeric complexes; Oligomeric structure; Phosphorylation; Small heat shock proteins