Abstract
HP1043 is an essential orphan response regulator of Helicobacter pylori orchestrating multiple crucial cellular processes. Classified as a member of the OmpR/PhoB family of two-component systems, HP1043 exhibits a highly degenerate receiver domain and evolved to function independently of phosphorylation. Here, we investigated the HP1043 binding mode to a target sequence in the hp1227 promoter (Php1227). Scanning mutagenesis of HP1043 DNA-binding domain and consensus sequence led to the identification of residues relevant for the interaction of the protein with a target DNA. These determinants were used as restraints to guide a data-driven protein-DNA docking. Results suggested that, differently from most other response regulators of the same family, HP1043 binds in a head-to-head conformation to the Php1227 target promoter. HP1043 interacts with DNA largely through charged residues and contacts with both major and minor grooves of the DNA are required for a stable binding. Computational alanine scanning on molecular dynamics trajectory was performed to corroborate our findings. Additionally, in vitro transcription assays confirmed that HP1043 positively stimulates the activity of RNA polymerase.
Highlights
Helicobacter pylori is a widespread human pathogen recognized as a class I carcinogen by the World Health Organization
The ability of this bacterium to colonize the harsh niche of the stomach and to establish a persistent infection depends on the coordinated expression of several genes, including virulence factors
The alignment of experimentally validated HP1043 binding sites led to the definition of a consensus sequence composed by the repetition of two TTTAAG hexamers separated by a 5 bp spacer, with a lower degree of sequence conservation for the second hemi-site [13]
Summary
Helicobacter pylori is a widespread human pathogen recognized as a class I carcinogen by the World Health Organization. It represents the primary cause of severe gastrointestinal diseases such as peptic ulcer, gastric adenocarcinoma, and MALT lymphoma [1,2]. The ability of this bacterium to colonize the harsh niche of the stomach and to establish a persistent infection depends on the coordinated expression of several genes, including virulence factors. Only 17 transcriptional regulators out of approximately 1500 predicted open reading frames (ORFs) have been identified and partially characterized [3]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
