title: Structural insight into the thermostable NADP(+)-dependent meso-diaminopimelate dehydrogenase from Ureibacillus thermosphaericus.
abstract: Crystal structures of the thermostable meso-diaminopimelate dehydrogenase (DAPDH) from Ureibacillus thermosphaericus were determined for the enzyme in the apo form and in complex with NADP(+) and N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid. The main-chain coordinates of the enzyme showed notable similarity to those of Symbiobacterium thermophilum DAPDH. However, the subunit arrangement of U. thermosphaericus DAPDH (a dimer) was totally different from that of the S. thermophilum enzyme (a hexamer). Structural comparison with the dimeric enzyme from the mesophile Corynebacterium glutamicum revealed that the presence of large numbers of intrasubunit and intersubunit hydrophobic interactions, as well as the extensive formation of intersubunit ion-pair networks, were likely to be the main factors contributing to the higher thermostability of U. thermosphaericus DAPDH. This differs from S. thermophilum DAPDH, within which the unique hexameric assembly is likely to be responsible for its high thermostability. Analysis of the active site of U. thermosphaericus DAPDH revealed the key factors responsible for the marked difference in substrate specificity between DAPDH and the D-amino acid dehydrogenase recently created from DAPDH by introducing five point mutations [Akita et al. (2012). Biotechnol. Lett. 34, 1693-1699; 1701-1702].
authors.affiliation: Applied Molecular Microbiology and Biomass Chemistry, Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Hironaga
authors.initials: H
authors.lastname: Akita
authors.affiliation: Division of Rare Sugar Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan.
authors.forename: Tomonari
authors.initials: T
authors.lastname: Seto
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering, Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka 535-8585, Japan.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Ohshima
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Sakuraba
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009249:NADP / Q000378:metabolism*; D058641:Planococcaceae / Q000201:enzymology*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D009249:NADP; D000594:Amino Acid Oxidoreductases; C020032:diaminopimelate dehydrogenase
keywords: Ureibacillus thermosphaericus; meso-diaminopimelate dehydrogenase