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Hyun JS, Pun R, Park SJ, Lee BJ. Effect of Divalent Metal Ions on the Ribonuclease Activity of the Toxin Molecule HP0894 from Helicobacter pylori. Life (Basel) 2024; 14:225. [PMID: 38398734 PMCID: PMC10890551 DOI: 10.3390/life14020225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024] Open
Abstract
Bacteria and archaea respond and adapt to environmental stress conditions by modulating the toxin-antitoxin (TA) system for survival. Within the bacterium Helicobacter pylori, the protein HP0894 is a key player in the HP0894-HP0895 TA system, in which HP0894 serves as a toxin and HP0895 as an antitoxin. HP0894 has intrinsic ribonuclease (RNase) activity that regulates gene expression and translation, significantly influencing bacterial physiology and survival. This activity is influenced by the presence of metal ions such as Mg2+. In this study, we explore the metal-dependent RNase activity of HP0894. Surprisingly, all tested metal ions lead to a reduction in RNase activity, with zinc ions (Zn2+) causing the most significant decrease. The secondary structure of HP0894 remained largely unaffected by Zn2+ binding, whereas structural rigidity was notably increased, as revealed using CD analysis. NMR characterized the Zn2+ binding, implicating numerous His, Asp, and Glu residues in HP0894. In summary, these results suggest that metal ions play a regulatory role in the RNase activity of HP0894, contributing to maintaining the toxin molecule in an inactive state under normal conditions.
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Affiliation(s)
- Ja-Shil Hyun
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 21936, Republic of Korea
| | - Rabin Pun
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 21936, Republic of Korea
| | - Sung Jean Park
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon 21936, Republic of Korea
| | - Bong-Jin Lee
- College of Pharmacy, Ajou University, 206 World Cup-ro, Yeongtong-gu, Suwon 16499, Republic of Korea
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Wang X, Kan Y, Bai K, Xu X, Chen X, Yu C, Shi J, Jiang N, Li J, Luo L. A novel double-ribonuclease toxin-antitoxin system linked to the stress response and survival of Acidovorax citrulli. Microbiol Spectr 2023; 11:e0216923. [PMID: 37819152 PMCID: PMC10714953 DOI: 10.1128/spectrum.02169-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/30/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE Bacterial fruit blotch (BFB), which is caused by the seed-borne bacterium Acidovorax citrulli, is a devastating disease affecting cucurbit crops throughout the world. Although seed fermentation and treatment with disinfectants can provide effective management of BFB, they cannot completely guarantee pathogen-free seedstock, which suggests that A. citrulli is a highly stress-resistant pathogen. Toxin-antitoxin (TA) systems are common among a diverse range of bacteria and have been reported to play a role in bacterial stress response. However, there is currently much debate about the relationship between TA systems and stress response in bacteria. The current study characterized a novel TA system (Aave_1720-Aave_1719) from A. citrulli that affects both biofilm formation and survival in response to sodium hypochlorite stress. The mechanism of neutralization differed from typical TA systems as two separate mechanisms were associated with the antitoxin, which exhibited characteristics of both type II and type V TA systems. The Aave_1720-Aave_1719 system described here also constitutes the first known report of a double-ribonuclease TA system in bacteria, which expands our understanding of the range of regulatory mechanisms utilized by bacterial TA systems, providing new insight into the survival of A. citrulli in response to stress.
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Affiliation(s)
- Xudong Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Yumin Kan
- Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, New York, USA
| | - Kaihong Bai
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Xiaoli Xu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Xing Chen
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Chengxuan Yu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Jia Shi
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Na Jiang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Jianqiang Li
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Laixin Luo
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
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