MazF Endoribonucleolytic Toxin Conserved in <i>Nitrospira</i> Specifically Cleaves the AACU, AACG, and AAUU Motifs

• Main Authors: Rie Aoi, Tatsuki Miyamoto, Akiko Yokota, Yuri Ota, Hirotsugu Fujitani, Satoshi Tsuneda, Naohiro Noda
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Toxins
• Subjects: <i>Nitrospira</i>; toxin-antitoxin systems; MazF; sequence-specificity; RNase
• Online Access: https://www.mdpi.com/2072-6651/12/5/287

MazF is an endoribonucleolytic toxin that cleaves intracellular RNAs in sequence-specific manners. It is liberated in bacterial cells in response to environmental changes and is suggested to contribute to bacterial survival by inducing translational regulation. Thus, determining the cleavage specificity provides insights into the physiological functions of MazF orthologues. <i>Nitrospira</i>, detected in a wide range of environments, is thought to have evolved the ability to cope with their surroundings. To investigate the molecular mechanism of its environmental adaption, a MazF module from <i>Nitrospira</i> strain ND1, which was isolated from the activated sludge of a wastewater treatment plant, is examined in this study. By combining a massive parallel sequencing method and fluorometric assay, we detected that this functional RNA-cleaving toxin specifically recognizes the AACU, AACG, and AAUU motifs. Additionally, statistical analysis suggested that this enzyme regulates various specific functions in order to resist environmental stresses.