Polyphosphate binds to the principal sigma factor of RNA polymerase during starvation response in Helicobacter pylori.

Abstract

Helicobacter pylori persists deep in the human gastric mucus layer in a harsh, nutrient-poor environment. Survival under these conditions depends on the ability of this human pathogen to invoke starvation/stress responses when needed. Unlike many bacteria, H. pylori lacks starvation/stress-responding alternative sigma factors, suggesting an additional mechanism might have evolved in this bacterium. Helicobacter pylori produces polyphosphate; however, the role and target of polyphosphate during starvation/stress have not been identified. Here we show that polyphosphate accumulated during nutrient starvation directly targets transcriptional machinery by binding to the principal sigma factor in H. pylori, uncovering a novel mechanism in microbial stress response. A positively charged Lys-rich region at the N-terminal domain of the major sigma factor is identified as the binding region for polyphosphate (region P) in vivo and in vitro, revealing a new element in sigma 70 family proteins. This interaction is biologically significant because mutant strains defective in the interaction undergo premature cell death during starvation. We suggested that polyphosphate is a second messenger employed by H. pylori to mediate gene expression during starvation/stress. The putative 'region P' is present in sigma factors of other human pathogens, suggesting that the uncovered interaction might be a general strategy employed by other pathogens.

• Authors: Zhao Xu Yang, Yan Ning Zhou, Yi Yang, Ding Jun Jin
• Journal: Molecular microbiology (Mol Microbiol) Vol. 77 Issue 3 Pg. 618-27 (Aug 2010) ISSN: 1365-2958 [Electronic] England
• PMID: 20553390 (Publication Type: Journal Article, Research Support, N.I.H., Intramural)

Chemical References

• Bacterial Proteins
• Polyphosphates
• Sigma Factor
• RNA polymerase sigma 70
• DNA-Directed RNA Polymerases

Topics

• Amino Acid Sequence
• Bacterial Proteins (chemistry, genetics, metabolism)
• DNA-Directed RNA Polymerases (chemistry, genetics, metabolism)
• Gene Expression Regulation, Bacterial
• Helicobacter pylori (chemistry, genetics, metabolism)
• Molecular Sequence Data
• Polyphosphates (metabolism)
• Protein Binding
• Protein Structure, Tertiary
• Sigma Factor (chemistry, genetics, metabolism)