2D1Y

Crystal structure of TT0321 from Thermus thermophilus HB8

Summary for 2D1Y

• Entry DOI: 10.2210/pdb2d1y/pdb
• Descriptor: hypothetical protein TT0321, NICOTINAMIDE-ADENINE-DINUCLEOTIDE (3 entities in total)
• Functional Keywords: strucrtural genomics, thermus thermophilus hb8, structural genomics, nppsfa, national project on protein structural and functional analyses, riken structural genomics/proteomics initiative, rsgi, oxidoreductase
• Biological source: Thermus thermophilus
• Total number of polymer chains: 4
• Total formula weight: 110617.98

Authors

Asada, Y.,Kunishima, N.,RIKEN Structural Genomics/Proteomics Initiative (RSGI) (deposition date: 2005-09-02, release date: 2006-03-02, Last modification date: 2023-10-25)

Primary citation

Asada, Y.,Endo, S.,Inoue, Y.,Mamiya, H.,Hara, A.,Kunishima, N.,Matsunaga, T.
Biochemical and structural characterization of a short-chain dehydrogenase/reductase of Thermus thermophilus HB8: a hyperthermostable aldose-1-dehydrogenase with broad substrate specificity.
Chem.Biol.Interact., 178:117-126, 2009

PubMed Abstract: Thermus 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.

PubMed: 18926808
DOI: 10.1016/j.cbi.2008.09.018

Experimental method

X-RAY DIFFRACTION (1.65 Å)