Peptide scanning-based identification of regions of gamma-II crystallin involved in thermal aggregation: evidence of the involvement of structurally analogous, helix-containing loops from the two double Greek key domains of the molecule.

Kundu, Bishwajit and Shukla, Anshuman and Guptasarma, Purnananda (2003) Peptide scanning-based identification of regions of gamma-II crystallin involved in thermal aggregation: evidence of the involvement of structurally analogous, helix-containing loops from the two double Greek key domains of the molecule. Archives of biochemistry and biophysics, 410 (1). pp. 69-75. ISSN 0003-9861

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Abstract

Gamma crystallin is one of three structural proteins present in great abundance in the fiber cells of the vertebrate eye lens. The protein displays a tendency to aggregate readily in the course of heating, cooling, being exposed to ultraviolet radiation, or rapid refolding. To investigate the molecular mechanisms underlying such aggregation, we have employed a peptide-scanning approach aimed at identifying regions of bovine gamma-II crystallin that may be involved in intermolecular interactions leading to aggregation, using assays that measure the competitive inhibition of such aggregation by reagents drawn from a group of contiguous (overlapping) peptides derived from the sequence of the protein itself. Our results suggest that two regions, comprising residues 61-74, and 145-159, play key roles in aggregative interactions. Intriguingly, the two regions (each containing a solvent-exposed, single-turn helix in the native structure) are located in structurally analogous positions in the two homologous double Greek key (beta sheet) domains of the protein, suggesting that helix-strand conversions may operate to facilitate intermolecular beta sheet interactions during aggregation.

Item Type:	Article
Additional Information:	Copyright of this article belongs to Elsevier Science.
Uncontrolled Keywords:	Protein aggregation; Unfolding intermediates; Lens crystallins; Peptide scanning
Subjects:	Q Science > QR Microbiology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	05 Jan 2012 15:06
Last Modified:	05 Jan 2012 15:06
URI:	http://crdd.osdd.net/open/id/eprint/253

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