Molecular dynamics simulations of phospholipases A2

An extensive molecular dynamics study of phospholipases A₂ frompancreatic bovine and Crotalus atrox venom has shown that thewell-conserved homologous core of the phospholipases A₂, includingthe so called catalytic network, is very stable during the courseof the calculations. The fluctuations which occur are locatedin segments which have significantly different three-dimensionalconformations in the two phospholipases A₂ studied, suggestingthat a particularly stable core conformation gives rise to alarge homologous family of similar three-dimensional structure.The calcium ion, which exhibits a crucial structural role inthe monomeric phospholipases A₂, appears not to be requiredto stabilize the C.atrox dimer. Moreover, the behaviour of thedimeric structure during the dynamics raises the question ofa possible dissociation of the two subunits into functionalmonomers.