Structural insights into the histidine-containing phosphotransfer protein and receiver domain of sensor histidine kinase suggest a complex model in the two-component regulatory system in Pseudomonas aeruginosa
Shao-Kang Chen,
Hong-Hsiang Guan,
Pei-Hsun Wu,
Li-Ting Lin,
Meng-Chun Wu,
Hwan-You Chang,
Nai-Chi Chen,
Chien-Chih Lin,
Phimonphan Chuankhayan,
Yen-Chieh Huang,
Pei-Ju Lin,
Chun-Jung Chen
Affiliations
Shao-Kang Chen
Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan City 701, Taiwan
Hong-Hsiang Guan
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Pei-Hsun Wu
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Li-Ting Lin
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Meng-Chun Wu
Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan City 701, Taiwan
Hwan-You Chang
Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 30013, Taiwan
Nai-Chi Chen
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Chien-Chih Lin
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Phimonphan Chuankhayan
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Yen-Chieh Huang
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Pei-Ju Lin
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
Chun-Jung Chen
Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan City 701, Taiwan
In Pseudomonas aeruginosa, an important opportunistic pathogen that causes numerous acute and chronic infections, the hybrid two-component system (TCS) regulates the swarming ability and biofilm formation with a multistep phosphorelay, and consists of hybrid-sensor histidine kinase (HK), histidine-containing phosphotransfer protein (Hpt) and response regulator (RR). In this work, two crystal structures of HptB and the receiver domain of HK PA1611 (PA1611REC) of P. aeruginosa have been determined in order to elucidate their interactions for the transfer of the phosphoryl group. The structure of HptB folds into an elongated four-helix bundle – helices α2, α3, α4 and α5, covered by the short N-terminal helix α1. The imidazole side chain of the conserved active-site histidine residue His57, located near the middle of helix α3, protrudes from the bundle and is exposed to solvent. The structure of PA1611REC possesses a conventional (β/α)5 topology with five-stranded parallel β-sheets folded in the central region, surrounded by five α-helices. The divalent Mg2+ ion is located in the negatively charged active-site cleft and interacts with Asp522, Asp565 and Arg567. The HptB–PA1611REC complex is further modeled to analyze the binding surface and interactions between the two proteins. The model shows a shape complementarity between the convex surface of PA1611REC and the kidney-shaped HptB with fewer residues and a different network involved in interactions compared with other TCS complexes, such as SLN1-R1/YPD1 from Saccharomyces cerevisiae and AHK5RD/AHP1 from Arabidopsis thaliana. These structural results provide a better understanding of the TCS in P. aeruginosa and could potentially lead to the discovery of a new treatment for infection.
