Creation of a new eye lens crystallin (Gambeta) through structure-guided mutagenic grafting of the surface of betaB2 crystallin onto the hydrophobic core of gammaB crystallin.

Kapoor, Divya and Singh, Balvinder and Subramanian, Karthikeyan and Guptasarma, Purnananda (2009) Creation of a new eye lens crystallin (Gambeta) through structure-guided mutagenic grafting of the surface of betaB2 crystallin onto the hydrophobic core of gammaB crystallin. The FEBS journal, 276 (12). pp. 3341-53. ISSN 1742-4658

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Abstract

The degree of conservation of three-dimensional folds in protein superfamilies is greater than that of amino acid sequences. Therefore, very different groups of residues (and schemes of residue packing) can be found displayed upon similar structural scaffolds. We have previously demonstrated the workability of a protein engineering-based method for rational mixing of the interior features of an all-beta enzyme with the substrate-binding and catalytic (surface) features of another enzyme whose sequence is not similar but which is structurally homologous to the first enzyme. Here, we extend this method to whole-protein surfaces and interiors. We show how two all-beta Greek key proteins, betaB2 crystallin and gammaB crystallin, can be recombined to produce a new protein through rational transplantation of the entire surface of betaB2 crystallin upon the structure of gammaB crystallin, without altering the latter's interior. This new protein, Gambeta, consists of 61 residues possessing the same identity at structurally equivalent positions in betaB2- and gammaB crystallin, 91 surface residues unique to betaB2 crystallin, and 27 interior residues unique to gammaB crystallin. Gambeta displays a mixture of the structural/biochemical characteristics, surface features and colligative properties of its progenitor crystallins. It also displays optical properties common to both progenitor crystallins (i.e. retention of transparency at high concentrations, as well as high refractivity). The folding of a protein with such a 'patchwork' residue ancestry suggests that interior/surface transplants involving all-beta proteins are a feasible engineering strategy.

Item Type:	Article
Additional Information:	Copyright of this article belongs to Wiley
Subjects:	Q Science > QR Microbiology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	08 Dec 2011 19:34
Last Modified:	08 Dec 2011 19:34
URI:	http://crdd.osdd.net/open/id/eprint/558

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