title: Thermodynamic and NMR analyses of NADPH binding to lipocalin-type prostaglandin D synthase.
abstract: Lipocalin-type prostaglandin D synthase (L-PGDS) is one of the most abundant proteins in human cerebrospinal fluid (CSF) with dual functions as a prostaglandin D2 (PGD2) synthase and a transporter of lipophilic ligands. Recent studies revealed that L-PGDS plays important roles in protecting against various neuronal diseases induced by reactive oxygen species (ROS). However, the molecular mechanisms of such protective actions of L-PGDS remain unknown. In this study, we conducted thermodynamic and nuclear magnetic resonance (NMR) analyses, and demonstrated that L-PGDS binds to nicotinamide coenzymes, including NADPH, NADP(+), and NADH. Although a hydrophilic ligand is not common for L-PGDS, these ligands, especially NADPH showed specific interaction with L-PGDS at the upper pocket of its ligand-binding cavity with an unusually bifurcated shape. The binding affinity of L-PGDS for NADPH was comparable to that previously reported for NADPH oxidases and NADPH in vitro. These results suggested that L-PGDS potentially attenuates the activities of NADPH oxidases through interaction with NADPH. Given that NADPH is the substrate for NADPH oxidases that play key roles in neuronal cell death by generating excessive ROS, these results imply a novel linkage between L-PGDS and ROS.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Shubin
authors.initials: S
authors.lastname: Qin
authors.affiliation: Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shimamoto
authors.affiliation: Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Maruno
authors.affiliation: Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kawahara
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address: ohkubo@phs.osaka-u.ac.jp.
authors.forename: Tadayasu
authors.initials: T
authors.lastname: Ohkubo
mesh_terms: D000818:Animals; D019746:Intramolecular Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D054834:Lipocalins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D009249:NADP / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D011487:Protein Conformation; D017382:Reactive Oxygen Species / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D054834:Lipocalins; D017382:Reactive Oxygen Species; D009249:NADP; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase
keywords: Isothermal titration calorimetry; Lipocalin-type prostaglandin D synthase; NADPH; Nuclear magnetic resonance