Probing the role of Val228 on the catalytic activity of Scytalidium catalase

Goc G., Balci S., Yorke B. A., Pearson A. R., YÜZÜGÜLLÜ KARAKUŞ Y.

BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS, cilt.1869, sa.8, 2021 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 1869 Sayı: 8
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1016/j.bbapap.2021.140662
  • Dergi Adı: BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, EMBASE, Food Science & Technology Abstracts, MEDLINE, Veterinary Science Database
  • Anahtar Kelimeler: Catalase, Oxidase, Lateral channel, Heme, Catechol, MACROMOLECULAR CRYSTALLOGRAPHY EXPERIMENTS, MOLECULAR EVOLUTION, THERMOPHILIC FUNGI, HPII, IDENTIFICATION, DIVERSITY, BEAMLINE, OXIDASE, BOND
  • Kocaeli Üniversitesi Adresli: Evet

Özet

Scytalidium catalase is a homotetramer including heme d in each subunit. Its primary function is the dismutation of H2O2 to water and oxygen, but it is also able to oxidase various small organic compounds including catechol and phenol. The crystal structure of Scytalidium catalase reveals the presence of three linked channels providing access to the exterior like other catalases reported so far. The function of these channels has been extensively studied, revealing the possible routes for substrate flow and product release. In this report, we have focussed on the semi-conserved residue Val228, located near to the vinyl groups of the heme at the opening of the lateral channel. Its replacement with Ala, Ser, Gly, Cys, Phe and Ile were tested. We observed a significant decrease in catalytic efficiency in all mutants with the exception of a remarkable increase in oxidase activity when Val228 was mutated to either Ala, Gly or Ser. The reduced catalytic efficiencies are characterized in terms of the restriction of hydrogen peroxide as electron acceptor in the active centre resulting from the opening of lateral channel inlet by introducing the smaller side chain residues. On the other hand, the increased oxidase activity is explained by allowing the suitable electron donor to approach more closely to the heme. The crystal structures of V228C and V228I were determined at 1.41 and 1.47 angstrom resolution, respectively. The lateral channels of the V228C and V228I presented a broadly identical chain of arranged waters to that observed for wild-type enzyme.