ALPHA-CRYSTALLIN C-TERMINAL DOMAIN - ON THE TRACK OF AN IG FOLD

New results obtained from a two-dimensional sequence analysis of the s mall heat shock protein (shsp) family are described. It is confirmed t hat the conserved C-terminal alpha-crystallin domain is essentially ma de of beta-strands, most probably two groups of beta-strands separated by a large loop. A direct correspondence between the putative beta-st rands that have been identified in shsps and the seven beta-strands of a classical immunoglobulin-like fold is proposed. The hypothesis that the shsp family could belong to the immunoglobulin superfamily (IgSF) is consistent with the ubiquitous distribution and the multifunctiona l properties of the crystallins that are now emerging. (C) 1998 Elsevi er Science B.V. All rights reserved.