Structural basis of Zn(II) induced metal detoxification and antibiotic resistance by histidine kinase CzcS in Pseudomonas aeruginosa
Fig 2
The Zn(II) binding site of CzcS SD.
(a) The coordination environment of the functionally relevant Zn(II) ion. The Zn(II) ion is shown as sphere in red, and the coordinated residues are shown as sticks in atomic color (C, yellow; N, blue; O, red). The 2Fo-Fc omit map is contoured at the 1σ level and is colored in gray. (b) The detailed interactions between the Zn(II) and the coordinated residues. The Zn(II) binds to CzcS in the tetrahedral coordination geometry. The Zn(II) ion is shown as red sphere. The residues in the first coordination sphere are depicted as stick representations with Cα atoms in yellow. The second shell hydrogen-bond interactions are indicated by the magenta-dotted line. (c) Metal and antibiotic tolerance plate assay. Wild type P. aeruginosa and its derivative strains are examined on LB plates that contain Zn(II) and MEPM antibiotic as follows: wild type P. aeruginosa with empty pAK1900 plasmid as the control (WT PAO1 pAK1900), czcS-deficient P. aeruginosa with the empty pAK1900 (PAO1△czcS pAK1900), czcS-deficient P. aeruginosa with wild type czcS encoded on pAK1900 (PAO1△czcS pCSAK), czcS-deficient P. aeruginosa complemented with the czcS mutants in pAK1900 (PAO1△czcS pCSAK H55A, PAO1△czcS pCSAK H55C, PAO1△czcS pCSAK D60A, PAO1△czcS pCSAK D60C, and PAO1△czcS pCSAK H55R).