RNA-hydrolyzing activity of metallo-β-lactamase IMP-1

• Published in: PloS one Vol. 15; no. 10; p. e0241557
• Main Authors: Kato, Yoshiki, Takahashi, Masayuki, Seki, Mineaki, Nashimoto, Masayuki, Shimizu-Ibuka, Akiko
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30-10-2020; Public Library of Science (PLoS)
• Subjects: Amides; Amino Acid Sequence; Amino acids; Antibiotics; beta-Lactamases - chemistry; beta-Lactamases - metabolism; Biology and Life Sciences; Cellular structure; Deoxyribonucleic acid; DNA; E coli; Enzymatic activity; Enzymes; Homology; Humans; Hydrolysis; Life sciences; Metallo-β-lactamase; Metallography; Models, Molecular; Nucleotide sequence; Pharmacy; Phenols; Physical Sciences; Protein Conformation; Protein structure; Proteins; Research and analysis methods; Ribonucleic acid; RNA; RNA - metabolism; Sodium; Substrate Specificity; Substrates; Tertiary structure; Thermotoga maritima - chemistry; Thermotoga maritima - enzymology; Thermotoga maritima - metabolism; tRNA; β Lactamase; β-Lactam antibiotics; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0241557

Metallo-β-lactamases (MBLs) hydrolyze a wide range of β-lactam antibiotics. While all MBLs share a common αβ/βα-fold, there are many other proteins with the same folding pattern that exhibit different enzymatic activities. These enzymes, together with MBLs, form the MBL superfamily. Thermotoga maritima tRNase Z, a tRNA 3' processing endoribonuclease of MBL-superfamily, and IMP-1, a clinically isolated MBL, showed a striking similarity in tertiary structure, despite low sequence homology. IMP-1 hydrolyzed both total cellular RNA and synthetic small unstructured RNAs. IMP-1 also hydrolyzed pre-tRNA, but its cleavage site was different from those of T. maritima tRNase Z and human tRNase Z long form, indicating a key difference in substrate recognition. Single-turnover kinetic assays suggested that substrate-binding affinity of T. maritima tRNase Z is much higher than that of IMP-1.