Novel nonsense mutation in the katA gene of a catalase-negative Staphylococcus aureus strain

Abstract We report the first description of a rare catalase-negative strain of Staphylococcus aureus in Chile. This new variant was isolated from blood and synovial tissue samples of a pediatric patient. Sequencing analysis revealed that this catalase-negative strain is related to ST10 strain, which has earlier been described in relation to S. aureus carriers. Interestingly, sequence analysis of the catalase gene katA revealed presence of a novel nonsense mutation that causes premature translational truncation of the C-terminus of the enzyme leading to a loss of 222 amino acids. Our study suggests that loss of catalase activity in this rare catalase-negative Chilean strain is due to this novel nonsense mutation in the katA gene, which truncates the enzyme to just 283 amino acids.

Proteome Analysis of a Catalase-deficient Isogenic Mutant of Helicobacter pylori 26695

Helicobacter pylori, a gram-negative bacterium, is a causative agent of gastroduodenal diseases of human. Human immune system produces harmful reactive oxygen species to kill this bacterium that locates the microaerophilic mucous layer. H. pylori harbors various antioxidant enzymes including SodB, KatA and AhpC to protect the oxygen toxicity. We removed the catalase gene (katA) from H. pylori 26695 genome, and the change of profile of the gene expression of the mutant was analyzed by high resolution 2-DE followed by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), tandem MS and microarray analysis. Eleven and 37 genes were upregulated and downregulated in the mutant respectively, either transcriptionally or translationally. Expression level of pfr and hp1588 that were decreased on protein level in the mutant was confirmed by RT-PCR analysis.

Expression and purification of Helicobacter pylori urease A subunit and catalase / 中国免疫学杂志

Objective:Investigated the effect of recombinant urease A subunit and catalase vaccines on protection against Helicobacter pylori (HP) infection Methods:Recombinant plasmids expressing UreA or KatA were constructed Expression was induced with IPTG,analyzed by SDS PAGE and Western blot UreA and KatA were purified with Bulk GST purification module Results:The recombinant plasmids could express GST UreA and GST KatA fusion proteins,which accounted for 35% and 19% of total bacteria proteins respectively,and could specially react with antibody against GST The purity of the purified UreA and KatA was over 95% Conclusion:The work laid a foundation for further studies of HP vaccine The recombinant vaccines may play an important role in preventing and treating HP infection and related diseases