2i5l
From Proteopedia
Crystal structure of Bacillus subtilis Cold Shock Protein variant Bs-CspB M1R/E3K/K65I
Overview
The bacterial cold shock proteins (Csp) are widely used as models for the experimental and computational analysis of protein stability. In a previous study, in vitro evolution was employed to identify strongly stabilizing mutations in Bs-CspB from Bacillus subtilis. The best variant found by this approach contained the mutations M1R, E3K and K65I, which raised the midpoint of thermal unfolding of Bs-CspB from 53.8 degrees C to 83.7 degrees C, and increased the Gibbs free energy of stabilization by 20.9 kJ mol(-1). Another selected variant with the two mutations A46K and S48R was stabilized by 11.1 kJ mol(-1). To elucidate the molecular basis of these stabilizations, we determined the crystal structures of these two Bs-CspB variants. The mutated residues are generally well ordered and provide additional stabilizing interactions, such as charge interactions, additional hydrogen bonds and improved side-chain packing. Several mutations improve the electrostatic interactions, either by the removal of unfavorable charges (E3K) or by compensating their destabilizing interactions (A46K, S48R). The stabilizing mutations are clustered at a contiguous surface area of Bs-CspB, which apparently is critically important for the stability of the beta-barrel structure but not well optimized in the wild-type protein.
About this Structure
2I5L is a Single protein structure of sequence from Bacillus subtilis. Full crystallographic information is available from OCA.
Reference
Optimized variants of the cold shock protein from in vitro selection: structural basis of their high thermostability., Max KE, Wunderlich M, Roske Y, Schmid FX, Heinemann U, J Mol Biol. 2007 Jun 15;369(4):1087-97. Epub 2007 Apr 12. PMID:17481655 Page seeded by OCA on Sun May 4 07:06:04 2008
