Abstract
Helicobacter pylori was already present in the stomach of primitive humans as they left Africa and spread through the world. Today, it still chronically infects more than 50% of the human population, causing, in some cases, severe diseases such as peptic ulcers and stomach cancer. Although successful life-lasting habitation of such harsh environment is made by combination of several special characteristic of H. pylori to against the challenge of the extreme acidity, it possesses relatively few transcriptional regulators. The carbon storage regulator (CsrA) family of RNA-binding proteins are global post-transcriptional regulators that mediate extensive changes in gene expression in bacteria. Various homologs are found in broad range of different species, including H. pylori. However, the regulated genes and target sequences by CsrA homolog (HP1442) in H. pylori are still unclear. Ligands of HP1442 were identified from a combinational library using systematic evolution of ligands by exponential enrichment (SELEX). The SELEX derived sequences contained consensus AGGA elements. A series of 1H-15N heteronuclear single quantum coherence (HSQC) spectra with or without selected ligands were also acquired to find out the binding region of HP1442.