RESUMEN
A cDNA encoding acidic phospholipase A(2)I(A.aAPLA(2)I)from Agkistrodon acutus was inserted into a bacterial expression vector and effectively expressed in E.coli RR1. The protein was produced as insoluble inclusion bodies. After partial purification by washing the inclusion bodies with Triton X-100, denaturing and refolding, the renatured recombinant protein was purified by FPLC column Superose(TM)12. The enzymatic acti-vity and platelet aggregation inhibiting effect of the expressed A.aAPLA(2)I is close to those of denatured-refolded native acidic PLA(2) from Agkistrodon halys Pallas, and has the same hemolytic activity as denatured-refolded basic phospholipase A(2) from Agkistrodon halys Pallas. The roles of various amino acid residues in the enzymatic activity and pharmacological activities of phospholipase A2 are discussed.
RESUMEN
The APLA(2) gene from Agkistrodon halys Pallas has been cloned into the expression plasmid pBLMVL2 and expressed in E. coli RR1. The molecular weight of the expressed product is approximately 14 kD as shown by SDS-PAGE, its expression level is about 30% of the total cellular proteins. The protein was produced as insoluble inclusion bodies. After partially purified by washing the inclusion bodies, the product was denatured and refolded into active form. Then, the expressed APLA(2) was purified by FPLC Superose (TM) 12 and was a single band as shown by SDS-PAGE. The purified expressed protein had specific activity as the native enzyme and cross-reacted with antisera prepared against the native enzyme. The successful expression of the APLA(2) gene from Agkistrodon halys Pallas provides a good basis for further structure-function studies.