title: Mechanism for the autophosphorylation of CheA histidine kinase: QM/MM calculations.
abstract: The CheA histidine kinase, a model of TCS (the two-component system), mediates the signal transduction pathway of bacterial chemotaxis via autophosphorylation. Since the TCSs are rarely found in mammalians, they have become attractive targets for the development of new antibiotics. To characterize the autophosphoryl-transfer mechanism of CheA histidine kinase, molecular dynamics simulations combined with quantum mechanics/molecular mechanics calculations were employed on the constructed 3D model of P1-P4-ATP complex. A two-step reaction mechanism was proposed and confirmed by our computations: the autophosphoryl-transfer reaction takes place followed by a rapid and reversible conformational change from ground state to prechemistry state. In addition, a two-dimensional potential energy surface was calculated for autophosphorylation, and the transition state displays an associative character. Moreover, we found Lys48 serves as the catalytic acid to stabilize transition state through a water-mediated proton-transfer pathway, and Glu67 acts as not only a hydrogen bond acceptor but also a structure anchor to modulate the imidazole ring of His45 in the active site. Our findings clearly provide a detailed autophosphoryl-transfer mechanism of CheA histidine kinase and thus are important for discovering new antibiotics.
authors.affiliation: Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Shi
authors.forename: Yunxiang
authors.initials: Y
authors.lastname: Lu
authors.forename: Xinyi
authors.initials: X
authors.lastname: Liu
authors.forename: Yingyi
authors.initials: Y
authors.lastname: Chen
authors.forename: Hualiang
authors.initials: H
authors.lastname: Jiang
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D020134:Catalytic Domain; D006860:Hydrogen Bonding; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D056004:Molecular Dynamics Simulation; D010766:Phosphorylation; D011789:Quantum Theory; D020124:Thermotoga maritima / Q000201:enzymology
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D000255:Adenosine Triphosphate