2I5L
Crystal structure of Bacillus subtilis Cold Shock Protein variant Bs-CspB M1R/E3K/K65I
Summary for 2I5L
| Entry DOI | 10.2210/pdb2i5l/pdb |
| Related | 1CSP 1CSQ 2ES2 2I5M |
| Descriptor | Cold shock protein cspB (2 entities in total) |
| Functional Keywords | oligonucleotide/oligosaccharide binding fold, cold shock domain, beta-barrel, dna binding protein, expression regulator, gene regulation |
| Biological source | Bacillus subtilis |
| Cellular location | Cytoplasm, nucleoid : P32081 |
| Total number of polymer chains | 1 |
| Total formula weight | 7382.17 |
| Authors | Max, K.E.A.,Heinemann, U. (deposition date: 2006-08-25, release date: 2007-05-22, Last modification date: 2023-08-30) |
| Primary citation | Max, K.E.,Wunderlich, M.,Roske, Y.,Schmid, F.X.,Heinemann, U. Optimized variants of the cold shock protein from in vitro selection: structural basis of their high thermostability. J.Mol.Biol., 369:1087-1097, 2007 Cited by PubMed Abstract: 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. PubMed: 17481655DOI: 10.1016/j.jmb.2007.04.016 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.55 Å) |
Structure validation
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