Molecular modeling of butyrylcholinesterase inhibition by cresyl saligenin phosphate

Presumably, aerotoxic syndrome is caused by the impact of tricresyl phosphate (TCP), a lubricating oil additive for aircraft engines, on the human body. The most toxic tri-ortho-isomer of this compound is metabolized in the body to give cresyl saligenin phosphate (CSP), which inhibits butyrylcholinesterase (BChE) giving phosphoserine. In this case, BChE acts as a stoichiometric bioscavenger irreversibly binding CSP and as a biomarker of exposure to low doses of TCP. The mechanism of CSP interaction with BChE at the initial stage of formation of the enzyme—inhibitor complex was studied by molecular modeling techniques. The results indicate that BChE interaction with the (R)-enantiomer of CSP in the most stable envelope conformation of the saligenin ring is most preferable. Comparison of the results obtained using different computation methods demonstrated that the best agreement with experimental data can be achieved by combining standard molecular docking methods with quantum mechanics methods for more accurate structure preparation.