title: Crystal structure of the catalase-peroxidase KatG W78F mutant from Synechococcus elongatus PCC7942 in complex with the antitubercular pro-drug isoniazid.
abstract: Isoniazid (INH) is a pro-drug that has been extensively used to treat tuberculosis. INH is activated by the heme enzyme catalase-peroxidase (KatG), but the mechanism of the activation is poorly understood, in part because the INH binding site has not been clearly established. Here, we observed that a single-residue mutation of KatG from Synechococcus elongatus PCC7942 (SeKatG), W78F, enhances INH activation. The crystal structure of INH-bound KatG-W78F revealed that INH binds to the heme pocket. The results of a thermal-shift assay implied that the flexibility of the SeKatG molecule is increased by the W78F mutation, allowing the INH molecule to easily invade the heme pocket through the access channel on the γ-edge side of the heme.
authors.affiliation: Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Kamachi
authors.affiliation: Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-1692, Japan; Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Hirabayashi
authors.affiliation: Faculty of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tamoi
authors.affiliation: Faculty of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
authors.affiliation: Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan. Electronic address: tada@b.s.osakafu-u.ac.jp.
authors.forename: Toshiji
authors.initials: T
authors.lastname: Tada
authors.affiliation: Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-1692, Japan. Electronic address: keiwada@med.miyazaki-u.ac.jp.
authors.forename: Kei
authors.initials: K
authors.lastname: Wada
mesh_terms: D019943:Amino Acid Substitution; D000995:Antitubercular Agents / Q000737:chemistry*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D006418:Heme / Q000737:chemistry; D007538:Isoniazid / Q000737:chemistry*; D020125:Mutation, Missense; D010544:Peroxidases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D046940:Synechococcus / Q000201:enzymology* / Q000235:genetics
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D006418:Heme; D010544:Peroxidases; C081610:catalase-peroxidase, bacteria; D007538:Isoniazid
keywords: Catalase–peroxidase; Crystal structure; Isoniazid; KatG