ATP binding subunit is known as a subunit of ABC transporter, providing energy through the binding of ATP with the subunit and the subsequent hydrolysis reaction of the bound ATP. In this study, density functional theory (DFT) method was used to study the ATP hydrolysis reaction in HisP protein, an ATP binding subunit of Histidine permease HisQMP2, by considering the ATP binding site, especially the γ-phosphate group, surrounding residues and water molecules. Based on DFT calculations, we proposed that ATP hydrolysis is initiated by the formation of Mg2+ mediated coordinate complex followed by the nucleophilic attack of a single water molecule (Water437) on the γ-phosphate; the hydrolysis product ADP acts as a leaving group. The transition state structure was determined by an approximate saddle-point search.
- Adenosine-triphosphate hydrolysis
- Adenosine-tripohosphate binding cassette transporter
- Chemical reaction mechanism
- Density function theory calculation
- HisP protein
- Transition state