Identification of the site of oxidase substrate binding in Scytalidium thermophilum catalase

Karakus Y., GOC G., BALCI S., YORKE B. A., Trinh C. H., McPherson M. J., ...More

ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY, vol.74, pp.979-985, 2018 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 74
  • Publication Date: 2018
  • Doi Number: 10.1107/s2059798318010628
  • Journal Name: ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.979-985
  • Keywords: catalase, Scytalidium thermophilum, oxidase, 3-amino-1,2,4-triazole, NADPH, binding pocket, lateral channel, MACROMOLECULAR CRYSTALLOGRAPHY EXPERIMENTS, X-RAY-DIFFRACTION, PENICILLIUM VITALE, ESCHERICHIA-COLI, PHENOL OXIDASE, REFINEMENT, PROTEIN, AMINOTRIAZOLE, PARAMETERS, DIVERSITY
  • Kocaeli University Affiliated: Yes

Abstract

The catalase from Scytalidium thermophilum is a homotetramer containing a heme d in each active site. Although the enzyme has a classical monofunctional catalase fold, it also possesses oxidase activity towards a number of small organics, including catechol and phenol. In order to further investigate this, the crystal structure of the complex of the catalase with the classical catalase inhibitor 3-amino-1,2,4-triazole (3TR) was determined at 1.95 angstrom resolution. Surprisingly, no binding to the heme site was observed; instead, 3TR occupies a binding site corresponding to the NADPH-binding pocket in mammalian catalases at the entrance to a lateral channel leading to the heme. Kinetic analysis of site-directed mutants supports the assignment of this pocket as the binding site for oxidase substrates.