2d1y
Crystal structure of TT0321 from Thermus thermophilus HB8
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThermus thermophilus HB8 is a hyperthermophilic bacterium, thriving at environmental temperature near 80 degrees C. The genomic analysis of this bacterium predicted 18 genes for proteins belonging to the short-chain dehydrogenase/reductases (SDR) superfamily, but their functions remain unknown. A SDR encoded in a gene (TTHA0369) was chosen for functional and structural characterization. Enzymatic assays revealed that the recombinant tetrameric protein has a catalytic activity as NAD(+)-dependent aldose 1-dehydroganse, which accepts various aldoses such as d-fucose, d-galactose, d-glucose, l-arabinose, cellobiose and lactose. The enzyme also oxidized non-sugar alicyclic alcohols, and was competitively inhibited by hexestrol, 1,10-phenanthroline, 2,3-benzofuran and indole. The enzyme was stable at pH 2-13 and up to 85 degrees C. We have determined the crystal structure of the enzyme-NAD(+) binary complex at 1.65A resolution. The structure provided evidence for the strict coenzyme specificity and broad substrate specificity of the enzyme. Additionally, it has unusual features, aromatic-aromatic interactions among Phe141 and Phe249 in the subunit interface and hydrogen networks around the C-terminal Asp-Gly-Gly sequence at positions 242-244. Stability analysis of the mutant D242N, F141A and F249A enzymes indicated that the two unique structural features contribute to the hyperthermostability of the enzyme. This study demonstrates that aldose 1-dehydrogenase is a member of the SDR superfamily, and provides a novel structural basis of thermostability. Biochemical and structural characterization of a short-chain dehydrogenase/reductase of Thermus thermophilus HB8: a hyperthermostable aldose-1-dehydrogenase with broad substrate specificity.,Asada Y, Endo S, Inoue Y, Mamiya H, Hara A, Kunishima N, Matsunaga T Chem Biol Interact. 2009 Mar 16;178(1-3):117-26. doi: 10.1016/j.cbi.2008.09.018. , Epub 2008 Sep 24. PMID:18926808[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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