Substrate gating confers steroid specificity to estrogen sulfotransferase

Evgeniy V. Petrotchenko, Mary E. Doerflein, Yoshimitsu Kakuta, Lars C. Pedersen, Masahiko Negishi

研究成果: ジャーナルへの寄稿学術誌査読

48 被引用数 (Scopus)


Estrogen sulfotransferase (EST) exhibits a high substrate specificity and catalytic efficiency toward estrogens such as estradiol (E2) but insignificant ability to sulfate hydroxysteroids such as dehydroepiandrosterone (DHEA). To provide the structural basis for this estrogen specificity, we mutated amino acid residues that constitute the substrate-binding site of EST. Among these mutants, only Tyr-81 decreased E2 and increased DHEA sulfotransferase activities. Substitution for Tyr-81 by smaller hydrophobic residues increased K(m(E2)) for E2 activity, whereas the k(cat(E2)) remained relatively constant. The Y81L mutant exhibited the same DHEA activity as wild-type hydroxysteroid sulfotransferase, for which K(m(DHEA)) remained relatively constant, and k(cat(DHEA)) was markedly increased. The side chain of Tyr-81 is directed at the A-ring of the E2 molecule in the substrate-binding pocket of EST, constituting a steric gate with Phe-142 sandwiching E2 from the opposite side. The present mutagenesis study indicates that the 3β-hydroxyl group of the DHEA molecule is excluded from the catalytic site of EST through steric hindrance of Tyr-81 with the C- 19 methyl group of DHEA. Thus, this stricture-like gating caused by steric hindrance appears to be a structural principle for conferring estrogen specificity to EST.

ジャーナルJournal of Biological Chemistry
出版ステータス出版済み - 10月 15 1999

!!!All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学


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