Identification of the Acidification Mechanism of the Optimal pH for RNase He1.

Autor: Takebe K; Oral & Maxillofacial Oncology and Surgery, Osaka University Graduate School of Dentistry., Suzuki M; Institute for Protein Research, Osaka University., Sangawa T; Institute for Protein Research, Osaka University., Motoyoshi N; School of Pharmacy, Nihon University., Itagaki T; School of Pharmacy, Nihon University., Kashima K; Oral & Maxillofacial Oncology and Surgery, Osaka University Graduate School of Dentistry., Uzawa N; Oral & Maxillofacial Oncology and Surgery, Osaka University Graduate School of Dentistry., Kobayashi H; School of Pharmacy, Nihon University.
Jazyk: angličtina
Zdroj: Biological & pharmaceutical bulletin [Biol Pharm Bull] 2023; Vol. 46 (12), pp. 1778-1786.
DOI: 10.1248/bpb.b23-00511
Abstrakt: Ribonuclease (RNase) He1 is a small ribonuclease belonging to the RNase T1 family. Most of the RNase T1 family members are active at neutral pH, except for RNase Ms, U2, and He1, which function at an acidic pH. We crystallized and analyzed the structure of RNase He1 and elucidated how the acidic amino residues of the α1β3- (He1:26-33) and β67-loops (He1:87-95) affect their optimal pH. In He1, Ms, and U2, the hydrogen bonding network formed by the acidic amino acids in the β67-loop suggested that the differences in the acidification mechanism of the optimum pH specified the function of these RNases. We found that the amino acid sequence of the β67-loop was not conserved and contributed to acidification of the optimum pH in different ways. Mutations in the acidic residues in He1 promoted anti-tumor growth activity, which clarified the role of these acidic amino residues in the binding pocket. These findings will enable the identification of additional targets for modifying pH-mediated enzymatic activities.
Databáze: MEDLINE