Dna restriction enzymes

Vectors and mutant strains used in this study are listed in Supplementary Table S1. All standard methods of DNA manipulation, such as plasmid isolation by alkaline lysis, restriction endonuclease digestion, and ligation, were performed according to the protocols of Sambrook et al. (1989) . Helicobacter pylori genomic DNA was prepared using the diaGene kit for DNA extraction from cell cultures (diaGene, Russia). Single DNA fragments or PCR amplification products for cloning or sequencing purposes were purified from agarose gels using Cleanup Standard Kit (Evrogen, Russia). DNA restriction enzymes were obtained from Fermentas (Thermo Fisher Scientific, USA) and were used according to the directions of the manufacturers.

All the strains used in this study were from Fujian Agriculture and Forestry University (Fujian, China). PCR ingredients and DNA restriction enzymes were purchased from Thermo Fisher Scientific (Waltham, MA, United States). Taq DNA polymerase and T4 DNA ligase were purchased from Takara biotechnology Co., Ltd. (Dalian, China). Anti maltose binding protein (MBP) tag monoclonal antibody was purchased from Abgent (San Diego, CA, United States), and HRP-labeled goat anti-mouse IgG was from Boster Biological Technology Co. (Wuhan, China). All other reagents used were of analytical reagent grade.