Cloning and Sequencing of Genes Encoding Phospholipase A₂ from
Agkistrodon acutus

LIU Xiao-Long, PAN Hua, YANG Guan-Zhen, WU Xiang-Fu and ZHOU Yuan-Cong^*
( Shanghai Institute of Biochemistry, the Chinese Academy of Science, Shanghai 200031, China )

Abstract　　 Synthetic oligonucleotides were used to amplify phospholipase A₂ (PLA₂) gene by RT-PCR from total RNA of snake Agkistrodon acutus venom gland. The PCR products were subcloned and positive clones were screened with acidic PLA₂ gene from Agkistrodon halys Pallas. Finally, four cDNAs of PLA₂ isoenzymes were isolated. Their complete sequences were determined by bidirectional sequencing and their amino acid sequences were deduced. They were designated as A.aAPLA₂I、A.aAPLA₂II、A.aBPLA₂ and A.aLys⁴⁹-PLA₂ according to their isoelectric points calculated by computer and special structure characteristics respectively. The amino acid sequence of 1－10 residues of A.aAPLA₂I deduced from the cDNA is identical to that of acidic PLA₂ which had been isolated from Agkistrodon acutus. A.aLys⁴⁹-PLA₂ is unique because of the usual Asp⁴⁹ is replaced by Lys⁴⁹, which may lower its enzymatic activity. Their similarity scores were calculated and compared by computer. The successful cloning of these isoenzymes genes may provide more information for the study on structure-function relationship of PLA₂ family.
Key Words　　Agkistrodon acutus; phospholipase A₂; gene; sequence analysis

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