Exploring Helicobacter pylori Histidyl tRNA synthetase as a drug target using biophysical and computational approaches

Helicobacter pylori infections represent a significant global health challenge, particularly due to the increasing prevalence of antibiotic resistance. This study aims to identify novel therapeutic targets by characterising H. pylori Histidyl tRNA synthetase (HpHRS), an enzyme essential for protein biosynthesis. We successfully cloned, expressed, and purified HpHRS using affinity chromatography and size exclusion chromatography techniques. Circular dichroism spectroscopy revealed conformational changes in HpHRS upon substrate binding, with a notable decrease in α-helical content and an increase in β-sheet structures. Fluorescence quenching studies confirmed the binding of L-histidine and ATP to the enzyme's active site. Virtual screening of the ZINC database identified two potential inhibitors, ZINC39960778 and ZINC30878996, which exhibited higher affinities than the natural substrate. Molecular dynamics simulations conducted over 100 ns demonstrated stable protein-ligand interactions, with the HRS-Histidyl Adenylate Monophosphate (HAM) complex showing the highest stability. Free energy landscape analysis indicated greater conformational freedom in ligand-bound complexes than apoproteins. These findings provide valuable insights into the structure and function of HpHRS, contributing to the development of new antibacterial agents targeting this crucial enzyme in H. pylori. Given the growing concern regarding antibiotic resistance, this study presents a promising avenue for designing new therapeutic strategies against H. pylori infections. Further research should focus on the experimental validation of the identified inhibitors and optimisation to develop potent and selective HpHRS inhibitors as potential antibacterial candidates.