2kp5

Publication Abstract from PubMed

To date, very few betagamma-crystallins have been identified and structurally characterized. Several of them have been shown to bind Ca(2+) and thereby enhance their stability without any significant change in structure. Although Ca(2+)-induced conformational changes have been reported in two putative betagamma-crystallins from Caulobacter crescentus and Yersinia pestis, they are shown to be partially unstructured, and whether they acquire a betagamma-crystallin fold is not known. We describe here a betagamma-crystallin domain, hahellin, its Ca(2+) binding properties and NMR structure. Unlike any other betagamma-crystallin, hahellin is characterized as a pre-molten globule (PMG) type of natively unfolded protein domain. It undergoes drastic conformational change and acquires a typical betagamma-crystallin fold upon Ca(2+) binding and hence acts as a Ca(2+)-regulated conformational switch. However, it does not bind Mg(2+). The intrinsically disordered Ca(2+)-free state and the close structural similarity of Ca(2+)-bound hahellin to a microbial betagamma-crystallin homologue, Protein S, which shows Ca(2+)-dependent stress response, make it a potential candidate for the cellular functions. This study indicates the presence of a new class of natively unfolded betagamma-crystallins and therefore the commencement of the possible functional roles of such proteins in this superfamily.

A natively unfolded betagamma-crystallin domain from Hahella chejuensis.,Srivastava AK, Sharma Y, Chary KV Biochemistry. 2010 Nov 16;49(45):9746-55. doi: 10.1021/bi101000m. Epub 2010 Oct , 22. PMID:20929244^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.