| Title | Identification and Characterization of HEPN‑MNT Type II TA System from Methanothermobacter thermautotrophicus ΔH |
|---|---|
| Author | Wonho Choi1,2, Anoth Maharjan1, Hae Gang Im3, Ji‑Young Park1, Jong‑Tae Park4*, and Jung‑Ho Park1* |
| Address | 1Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Republic of Korea, 2Present Address: 4D Convergence Technology Institute (National Key Technology Institute in University), Korea National University of Transportation, Jungpyeong 27909, Republic of Korea, 3BIORCHESTRA Co., LTD., Daejeon 34013, Republic of Korea, 4Department of Food Science and Technology, Chungnam National University, Daejeon 34134, Republic of Korea |
| Bibliography | Journal of Microbiology, 61(4),411-421, 2023, |
| DOI | 10.1007/s12275-023-00041-9 |
| Key Words | Toxin-antitoxin · HEPN-MNT · Endonuclease · Methanothermobacter thermautotropicus ΔH |
| Abstract | Toxin-antitoxin (TA) systems are widespread in bacteria and archaea plasmids and genomes to regulate DNA replication, gene transcr!ption, or protein translation. Higher eukaryotic and prokaryotic nucleotide-binding (HEPN) and minimal nucleotidyltransferase (MNT) domains are prevalent in prokaryotic genomes and constitute TA pairs. However, three gene pairs (MTH304/305, 408/409, and 463/464) of Methanothermobacter thermautotropicus ΔH HEPN-MNT family have not been studied as TA systems. Among these candidates, our study characterizes the MTH463/MTH464 TA system. MTH463 expression inhibited Escherichia coli growth, whereas MTH464 did not and blocked MTH463 instead. Using site-directed MTH463 mutagenesis, we determined that amino acids R99G, H104A, and Y106A from the R[ɸX]4-6H motif are involved with MTH463 cell toxicity. Furthermore, we established that purified MTH463 could degrade MS2 phage RNA, whereas purified MTH464 neutralized MTH463 activity in vitro. Our results indicate that the endonuclease toxin MTH463 (encoding a HEPN domain) and its cognate antitoxin MTH464 (encoding the MNT domain) may act as a type II TA system in M. thermautotropicus ΔH. This study provides initial and essential information studying TA system functions, primarily archaea HEPN-MNT family. |