Abstract
Helicobacter pylori infection can lead to the development of gastric and duodenal ulcers and gastric cancer. In recent years, the efficacy of the standard therapy has been falling, necessitating ongoing efforts to identify new drug targets. Due to their important role in chemotaxis and nutrient uptake, periplasmic binding proteins (PBPs) represent potential targets for new antimicrobial agents that have not yet been fully explored and exploited. The H. pylori PBP YckK is homologous to polar amino acid-binding proteins from other bacteria. The yckK gene overlaps the gene tcyB—a gene annotated as a polar amino acid-transporting permease. Purified recombinant YckK behaved as a monomer in solution. Crystals of YckK were grown by the hanging drop vapour diffusion method using PEG 3350 as the precipitating agent. The crystals belong to the primitive triclinic space group P1 with unit cell parameters a = 63.0, b = 63.5, c = 74.6 Å, α = 72.5, β = 68.3, γ = 69.4°. X-ray diffraction data were collected to 1.8 Å resolution using synchrotron radiation. Molecular replacement using this data revealed that the asymmetric unit contains three subunits: two in the open and one in the closed conformation.
Highlights
Helicobacter pylori is a Gram-negative spiral-shaped bacterium that possesses a number of flagella located at the cell pole
Recombinant H. pylori SS1 YckK lacking the periplasm-targeting peptide was expressed in E. coli BL21 cells transformed with the pet151/D-TOPO expression vector
Electrophoretic homogeneity of the purified protein was more than 95% as determined by Coomassie Blue staining of an SDS-PAGE gel (Figure 1)
Summary
Helicobacter pylori is a Gram-negative spiral-shaped bacterium that possesses a number of flagella located at the cell pole. H. pylori infection is associated with chronic gastritis, and is an established risk factor for the development of gastric and duodenal ulcers. Infection is associated with the development of more severe conditions such as MALT-lymphoma and gastric cancer [2]. The efficacy of the standard triple therapy comprising one proton pump inhibitor, clarithromycin, and amoxicillin or metronidazole has been falling, largely due to increasing antibiotic resistance [3]. Bismuth quadruple therapy can be used as an alternative in cases where standard treatment fails, this therapy still relies on the use of antibiotics to which resistance is growing, such as metronidazole [3]. Ongoing efforts to identify new drug targets for antibiotic development are needed
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