2ioy
From Proteopedia
Crystal structure of Thermoanaerobacter tengcongensis ribose binding protein
Overview
ABSTRACT: BACKGROUND: Comparison of experimentally determined mesophilic and thermophilic homologous protein structures is an important tool for understanding the mechanisms that contribute to thermal stability. Of particular interest are pairs of homologous structures that are structurally very similar, but differ significantly in thermal stability. RESULTS: We report the X-ray crystal structure of a Thermoanaerobacter tengcongensis ribose binding protein (tteRBP) determined to 1.9A resolution. We find that tteRBP is significantly more stable (appTm value ~102AdegreesC) than the mesophilic Escherichia coli ribose binding protein (ecRBP) (appTm value ~56AdegreesC). The tteRBP has essentially the identical backbone conformation (0.41A RMSD of 235/271 C-alpha positions and 0.65A RMSD of 270/271 C-alpha positions) as ecRBP. Classification of the amino acid substitutions as a function of structure therefore allows the identification of amino acids which potentially contribute to the observed thermal stability of tteRBP in the absence of large structural heterogeneities. CONCLUSIONS: The near identity of backbone structures of this pair of proteins entails that the significant differences in their thermal stabilities are encoded exclusively by the identity of the amino acid side-chains. Furthermore, the degree of sequence divergence is strongly correlated with structure; with a high degree of conservation in the core progressing to increased diversity in the boundary and surface regions. Different factors that may possibly contribute to thermal stability appear to be differentially encoded in each of these regions of the protein. The tteRBP/ecRBP pair therefore offers an opportunity to dissect contributions to thermal stability by side-chains alone in the absence of large structural differences.
About this Structure
2IOY is a Single protein structure of sequence from Thermoanaerobacter tengcongensis. Full crystallographic information is available from OCA.
Reference
The backbone structure of the thermophilic Thermoanaerobacter tengcongensis ribose binding protein is essentially identical to its mesophilic E. coli homolog., Cuneo MJ, Tian Y, Allert M, Hellinga HW, BMC Struct Biol. 2008 Mar 28;8(1):20. PMID:18373848 Page seeded by OCA on Wed Apr 16 23:06:41 2008
