Molecular dynamics simulation and molecular modelling studies on the insecticidal domain from jack bean urease

Urease is an enzyme which catalyses hydrolysis of urea to ammonia and carbon dioxide. Plant ureases but not bacterial ureases display insecticidal activity against insects with cathepsin B- and D-based digestive systems. It was found that a 10-kDa internal region of a plant urease exhibits this insecticidal activity, and more precisely it was predicted that a -hairpin motif within this region may be responsible for this activity by functioning as a membrane pore former. We carried out molecular dynamics study of the jack bean urease insecticidal region in the presence of explicit water and in water/hexane interface, in order to gain more insight into the structural changes and behaviour of the hairpin region in the membrane-like interfacial environment. The results indicate that the hairpin anchors well in the polar/non-polar interface. Subsequent modelling study of the insecticidal region clearly suggests that this region can form a -barrel assembly and thus supports our previous hypothesis that the insecticidal activity of plant ureases occurs through pore-forming -barrel assembly.