Search for conserved amino acid residues of the α-crystallin proteins of vertebrates.

ABSTRACT

[Formula see text]-crystallin is the major eye lens protein and a member of the small heat-shock protein (sHsp) family. [Formula see text]-crystallins have been shown to support lens clarity by preventing the aggregation of lens proteins. We performed the bioinformatics analysis of [Formula see text]-crystallin sequences from vertebrates to find conserved amino acid residues as the three-dimensional (3D) structure of [Formula see text]-crystallin is not identified yet. We are the first who demonstrated that the N-terminal region is conservative along with the central domain for vertebrate organisms. We have found that there is correlation between the conserved and structured regions. Moreover, amyloidogenic regions also correspond to the structured regions. We analyzed the amino acid composition of [Formula see text]-crystallin A and B chains. Analyzing the occurrence of each individual amino acid residue, we have found that such amino acid residues as leucine, serine, lysine, proline, phenylalanine, histidine, isoleucine, glutamic acid, and valine change their content simultaneously in A and B chains in different classes of vertebrates. Aromatic amino acids occur more often in [Formula see text]-crystallins from vertebrates than on the average in proteins among 17 animal proteomes. We obtained that the identity between A and B chains in the mammalian group is 0.35, which is lower than the published 0.60.