title: The anticancer natural product pironetin selectively targets Lys352 of alpha-tubulin.
abstract: Pironetin is a potent inhibitor of tubulin assembly and arrests cell cycle progression in M phase. Analyses of its structure-activity relationships suggested that pironetin covalently binds tubulin. To determine the binding site of pironetin, we synthesized biotinylated pironetin, which inhibited tubulin assembly both in vitro and in situ. The biotinylated pironetin selectively and covalently bound with tubulin. Partial digestion of biotinylated pironetin-treated tubulin by several proteases revealed that the binding site is the C-terminal portion of alpha-tubulin. By systematic alanine scanning, the pironetin binding site was determined to be Lys352 of alpha-tubulin. Lys352 is located at the entrance of a small pocket of alpha-tubulin, and this pocket faces the beta-tubulin of the next dimer. This is the first compound that covalently binds to the alpha subunit of tubulin and Lys352 of alpha-tubulin and inhibits the interaction of tubulin heterodimers.
authors.affiliation: Antibiotics Laboratory, RIKEN Discovery Research Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Usui
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakayama
authors.forename: Yukio
authors.initials: Y
authors.lastname: Tada
authors.forename: Naoki
authors.initials: N
authors.lastname: Kanoh
authors.forename: Masuo
authors.initials: M
authors.lastname: Kondoh
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Asao
authors.forename: Koji
authors.initials: K
authors.lastname: Takio
authors.forename: Hidenori
authors.initials: H
authors.lastname: Watanabe
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kitahara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Osada
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001665:Binding Sites / Q000187:drug effects; D002460:Cell Line; D002645:Chickens; D008239:Lysine / Q000737:chemistry*; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D011753:Pyrones / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D051381:Rats; D013329:Structure-Activity Relationship; D014404:Tubulin / Q000737:chemistry; D050257:Tubulin Modulators
chemical_list: D000970:Antineoplastic Agents; D011753:Pyrones; D014404:Tubulin; D050257:Tubulin Modulators; C088446:pironetin; D008239:Lysine