Molecular Dynamics Simulations of Bacillus Subtilis EngA – for Exploring Nucleotide Dependent Conformations

Essential Neisserial GTPase A (EngA) is a member of the TRAFAC class of GTPase superfamily. GTPases are molecular switches that switch between the GTP bound (On) state and the GDP bound (Off) state. This switching regulates many biological functions such as protein synthesis, ribosome biogenesis, cell multiplication etc. GTPases possess four highly conserved G-motifs (G1((GxxxxGK[ST])), G2(T), G3(DxxG), G4([NT][KQ]xD)) and one weakly conserved G5 (SAK) motif, which provides the facility to interact with guanine nucleotides. The P-loop of GTPases with a G1-motif interacts with the beta and gamma phosphates of GTP/GDP, the G2 and G3 motifs that interacts with gamma phosphate undergo large conformational changes termed Switch-I (Sw-I) and Switch-II (Sw-II). The G4 and G5 motifs stabilize the interaction with guanine bases.