Han, Kyung-Doo Matsuura, Atsushi Ahn, Hee-Chul Kwon, Ae-Ran Min, Yu-Hong Park, Hyo-Ju Won, Hyung-Sik Park, Sung-Jean Kim, Do-Young Lee, Bong-Jin 2024-01-20T17:34:39Z 2024-01-20T17:34:39Z 2021-09-02 2011-02 0021-9258 https://pubs.kist.re.kr/handle/201004/130703 Bacterial toxin-antitoxin (TA) systems are associated with many important cellular processes including antibiotic resistance and microorganism virulence. Here, we identify and structurally characterize TA molecules from the gastric pathogen, Helicobacter pylori. The HP0894 protein had been previously suggested, through our structural genomics approach, to be a putative toxin molecule. In this study, the intrinsic RNase activity and the bacterial cell growth-arresting activity of HP0894 were established. The RNA-binding surface was identified at three residue clusters: (Lys(8) and Ser(9)), (Lys(50)-Lys(54) and Glu(58)), and (Arg(80) and His(84)-Phe(88)). In particular, the -UA- and -CA- sequences in RNA were preferentially cleaved by HP0894, and residues Lys(52), Trp(53), and Ser(85)-Lys(87) were observed to be the main contributors to sequence recognition. The action of HP0894 could be inhibited by the HP0895 protein, and the HP0894-HP0895 complex formed an oligomer with a binding stoichiometry of 1:1. The N and C termini of HP0894 constituted the binding sites to HP0895. In contrast, the unstructured C-terminal region of HP0895 was responsible for binding to HP0894 and underwent a conformational change in the process. Finally, DNA binding activity was observed for both HP0895 and the HP0894-0895 complex but not for HP0894 alone. Taken together, it is concluded that the HP0894-HP0895 protein couple is a TA system in H. pylori, where HP0894 is a toxin with an RNase function, whereas HP0895 is an antitoxin functioning by binding to both the toxin and DNA. English AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC MULTIPLE SEQUENCE ALIGNMENT MESSENGER-RNA INTERFERASE PROGRAMMED CELL-DEATH ESCHERICHIA-COLI TRANSCRIPTIONAL AUTOREPRESSION CRYSTAL-STRUCTURE YEFM ANTITOXIN ACTIVE-SITE PROTEIN CLEAVAGE Functional Identification of Toxin-Antitoxin Molecules from Helicobacter pylori 26695 and Structural Elucidation of the Molecular Interactions Article 10.1074/jbc.M109.097840 1 JOURNAL OF BIOLOGICAL CHEMISTRY, v.286, no.6, pp.4842 - 4853 JOURNAL OF BIOLOGICAL CHEMISTRY 286 6 4842 4853 scie scopus 000286975700081 2-s2.0-79953006377 Biochemistry & Molecular Biology Biochemistry & Molecular Biology Article MULTIPLE SEQUENCE ALIGNMENT MESSENGER-RNA INTERFERASE PROGRAMMED CELL-DEATH ESCHERICHIA-COLI TRANSCRIPTIONAL AUTOREPRESSION CRYSTAL-STRUCTURE YEFM ANTITOXIN ACTIVE-SITE PROTEIN CLEAVAGE