Analysis of growth phase-dependent proteome profiles reveals differential regulation of mRNA and protein in Helicobacter pylori

Helicobacter pylori is a slow growing, microaerophilic bacterium that causes various gastric diseases. To understand the growth phase-dependent global regulation of protein in H. pylori, we analyzed the proteome profiles of H. pylori 26695 harvested during the course of in vitro culture. Temporal changes in protein profiles were assessed using three independent cultures harvested at 6, 12, 24, 36, 48, and 60 h. Compared with the protein spots obtained at 6 h, 151 protein spots obtained at other time points exhibited significantly altered intensity, with 57 of these protein spots identified by MALDI-TOF MS analysis. Clustering analysis showed that overall protein profile was coordinated in accordance with the growth phases of the culture. When we compared mRNA transcript levels of the identified proteins, obtained from RT-PCR analysis, with their protein levels, we observed substantial discrepancies in their patterns, suggesting that the transcriptome and proteome of H. pylori were differentially regulated during in vitro culture. Proteomic analysis also suggested that several H. pylori proteins underwent PTMs, some of which were modulated as a function of the growth phase of the culture. These findings indicate that H. pylori utilizes modulation of protein regulation and PTM as mechanisms to cope with changing growth environments. These observations should provide insight into the adaptive mechanisms employed by H. pylori within the context of growth environments.