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Structure of 4‐pyridoxolactonase from Mesorhizobium loti
Author(s) -
Kobayashi Jun,
Yoshikane Yu,
Yagi Toshiharu,
Baba Seiki,
Mizutani Kimihiko,
Takahashi Nobuyuki,
Mikami Bunzo
Publication year - 2014
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x14003926
Subject(s) - chemistry , stereochemistry , subclass , crystal structure , docking (animal) , zinc , pyridoxal , hydrolysis , enzyme , crystallography , biochemistry , biology , organic chemistry , medicine , nursing , antibody , immunology
4‐Pyridoxolactonase from Mesorhizobium loti catalyzes the zinc‐dependent lactone‐ring hydrolysis of 4‐pyridoxolactone (4PAL) to 4‐pyridoxic acid (4PA) in vitamin B 6 degradation pathway I. The crystal structures of 4‐pyridoxolactonase and its complex with 5‐pyridoxolactone (5PAL; the competitive inhibitor) were determined. The overall structure was an αβ/βα sandwich fold, and two zinc ions were coordinated. This strongly suggested that the enzyme belongs to subclass B3 of the class B β‐lactamases. In the complex structure, the carbonyl group of 5PAL pointed away from the active site, revealing why it acts as a competitive inhibitor. Based on docking simulation with 4PAL, 4PA and a reaction intermediate, 4‐pyridoxolactonase probably catalyzes the reaction through a subclass B2‐like mechanism, not the subclass B3 mechanism.