Cloning,functional expression,and characterization of an edema-producing Asp-49 phospholipase A2 from Trimeresurus mucrosquamatus

The snake-bite of Trimeresurus mucrosquamatus can cause severe edema and result in complications. Snake venom phospholipase A₂s are the major components responsible for causing edema. Therefore, understanding the edema-producing mechanism induced by the venom of T. mucrosquamatus can be important in treating the edema. In order to study the edema-producing effect, a venom Asp-49 phospholipase A₂ (TMV-D49-PLA₂) was cloned, sequenced, and functionally expressed in Escherichia coli. This expressed venom protein demonstrated specific phospholipase activities both in the digestion of lecithin in vitro and in inducing edema in rats in vivo. Therefore, the cloning and functional expression of the recombinant edema-producing protein are critical steps and should allow further characterization of the functional motifs responsible for both the edema-inducing activity and the development of therapeutic antiserum against the edema effect of the snake venom proteins.