アオノ リク
青野 陸
AONO RIKU
所属 生命科学部 生物工学科
職名 助教
言語種別 英語
発行・発表の年月 2012/06
形態種別 研究論文(学術雑誌)
査読 査読あり
標題 Dynamic, Ligand-dependent Conformational Change Triggers Reaction of Ribose-1,5-bisphosphate Isomerase from Thermococcus kodakarensis KOD1
執筆形態 不明
掲載誌名 JOURNAL OF BIOLOGICAL CHEMISTRY
出版社・発行元 AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
巻・号・頁 287(25),20784-20796
著者・共著者 Akira Nakamura,Masahiro Fujihashi,Riku Aono,Takaaki Sato,Yosuke Nishiba,Shosuke Yoshida,Ayumu Yano,Haruyuki Atomi,Tadayuki Imanaka,Kunio Miki
概要 Ribose-1,5-bisphosphate isomerase (R15Pi) is a novel enzyme recently identified as a member of an AMP metabolic pathway in archaea. The enzyme converts D-ribose 1,5-bisphosphate into ribulose 1,5-bisphosphate, providing the substrate for archaeal ribulose-1,5-bisphosphate carboxylase/oxygenases. We here report the crystal structures of R15Pi from Thermococcus kodakarensis KOD1 (Tk-R15Pi) with and without its substrate or product. Tk-R15Pi is a hexameric enzyme formed by the trimerization of dimer units. Biochemical analyses show that Tk-R15Pi only accepts the alpha-anomer of D-ribose 1,5-bisphosphate and that Cys(133) and Asp(202) residues are essential for ribulose 1,5-bisphosphate production. Comparison of the determined structures reveals that the unliganded and product-binding structures are in an open form, whereas the substrate-binding structure adopts a closed form, indicating domain movement upon substrate binding. The conformational change to the closed form optimizes active site configuration and also isolates the active site from the solvent, which may allow deprotonation of Cys(133) and protonation of Asp(202) to occur. The structural features of the substrate-binding form and biochemical evidence lead us to propose that the isomerase reaction proceeds via a cis-phosphoenolate intermediate.
DOI 10.1074/jbc.M112.349423
ISSNコード 00219258
PMID 22511789
PermalinkURL http://www.jbc.org/content/287/25/20784.long