Article info Vol. 3  No. 1   pp.  41 ~ 47
Title Crystal structure of a class 2 D-xylose isomerase from the human intestinal tract microbe Bacteroides thetaiotaomicron
Authors Byeong-Gu Han1,+, Seoung Min Bong1,+, Jea-Won Cho1,2, Myoung-Dong Kim2, Seung Jun Kim3 and Byung Il Lee1,*
Institutions 1Biomolecular Function Research Branch, Division of Convergence Technology, Research Institute, National Cancer Center, Goyang, Gyeonggi 410-769, Korea, 2Department of Biotechnology, Kangwon National University, Chuncheon, Kangwon 200-701, Korea, 3Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-333, Korea. *Correspondence: bilee@ncc.re.kr +These authors contributed equally to this work.
Abstract The human intestinal microbe Bacteroides thetaiotaomicron has an extensive starch utilization system and multiple genes that are involved in starch binding and utilization. We determined the structure of a xylose isomerase (XI) of Bacteroides thetaiotaomicron, which belongs to the class 2 XIs. Although the overall structures of XIs from different organisms were highly similar to each other, some large deviations were found in the class 1 and class 2 XIs; the long N-terminal extension of class 2 XIs made additional contact with the adjacent subunit of XI, and the C-terminal small α helical domain of XIs exhibited distinguishable structural features between the class 1 and class 2 XIs. However, the structures around the metal and substrate binding site were also almost identical regardless of the XI classes, suggesting common enzymological properties between the class 1 and class 2 XIs.