Maintenance of chaperone-like activity despite mutations in a conserved region of murine lens alphaB crystallin.
OBJECTIVE
To understand the relationship between certain conserved residues in alphaB crystallin and the chaperone-like function of the protein.


METHODS
In alphaB crystallin, residues H101 to R120 are highly conserved between alphaB crystallin and alphaA crystallin (85% identity), and between alphaB crystallin and the small heat shock protein hsp 27 (80% identity). We made three substitution mutants of alphaB crystallin: the single mutant F118A, and the double mutants K103L/H104I, and E110H/H111E.


RESULTS
Polyacrylamide gel electrophoresis revealed no decrease in aggregate size or measureable structural changes between them and the native structure. Using the insulin aggregation assay, all three mutants had identical chaperone-like activity to the wild-type recombinant alphaB crystallin.


CONCLUSIONS
Despite the high conservation in this area of sequence between alphaB crystallin, alphaA crystallin, and the small heat shock protein hsp 27, mutations F118A, K103L/H104I, and E110H/H111E did not significantly alter chaperone-like activity.
Hepburne-Scott
H W
HW
Division of Cell and Molecular Biology, School of Animal and Microbial Sciences, The University of Reading, Whiteknights, Reading, Berkshire, UK. Henry.Hepburne-scott@bbsrc.ac.uk
Crabbe
M J
MJ
D000818:Animals; D002417:Cattle; D003459:Crystallins / Q000235:genetics* / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology; D051379:Mice; D018832:Molecular Chaperones / Q000235:genetics* / Q000502:physiology; D016297:Mutagenesis, Site-Directed; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology
D003459:Crystallins; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins