title: Structural basis of stereospecific reduction by quinuclidinone reductase.
abstract: Chiral molecule (R)-3-quinuclidinol, a valuable compound for the production of various pharmaceuticals, is efficiently synthesized from 3-quinuclidinone by using NADPH-dependent 3-quinuclidinone reductase (RrQR) from Rhodotorula rubra. Here, we report the crystal structure of RrQR and the structure-based mutational analysis. The enzyme forms a tetramer, in which the core of each protomer exhibits the α/β Rossmann fold and contains one molecule of NADPH, whereas the characteristic substructures of a small lobe and a variable loop are localized around the substrate-binding site. Modeling and mutation analyses of the catalytic site indicated that the hydrophobicity of two residues, I167 and F212, determines the substrate-binding orientation as well as the substrate-binding affinity. Our results revealed that the characteristic substrate-binding pocket composed of hydrophobic amino acid residues ensures substrate docking for the stereospecific reaction of RrQR in spite of its loose interaction with the substrate.
authors: Daijiro
authors: D
authors: Takeshita
authors: Michihiko
authors: M
authors: Kataoka
authors: Takuya
authors: T
authors: Miyakawa
authors: Ken-Ichi
authors: K
authors: Miyazono
authors: Shoko
authors: S
authors: Kumashiro
authors: Takahiro
authors: T
authors: Nagai
authors: Nobuyuki
authors: N
authors: Urano
authors: Atsuko
authors: A
authors: Uzura
authors: Koji
authors: K
authors: Nagata
authors: Sakayu
authors: S
authors: Shimizu
authors: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. amtanok@mail.ecc.u-tokyo.ac.jp.
authors: Masaru
authors: M
authors: Tanokura