Isolation and biochemical characterization of a gamma-type phospholipase A2 inhibitor from Macropisthodon rudis snake serum

- Isolation of a novel gamma-type PLA2 inhibitory protein from Macropisthodon rudis snake serum.
- The amino acid sequences of the cDNAs were analyzed with other related inhibitors by multiple sequence alignment.
- Phylogenetic trees were constructed to study their evolutionary relationship.
- PLIγ neutralizes the enzymatic, inflammatory, and antibacterial activities of a PLA2 isolated from Agkistrodon acutus.

A novel phospholipaseA2 (PLA2) inhibitory protein (PLI) was purified from the serum of Macropisthodon rudis, a non-venomous snake mainly found in southern China. The molecular mass of the purified PLI was 160 kDa as determined by Superdex 200HR; however, the PLI protein had only one subunit of 25.4 kDa as determined by 12% SDS-PAGE, indicating an oligomeric protein. PLI cDNA obtained by PCR from the liver of Macropisthodon rudis, revealed 549 bps coding for a mature protein of 183 amino acid residues. Based on an amino acid sequence alignment with venomous and non-venomous snakes, this inhibitor was determined to be in the γ type family of PLI. In vitro experiments showed that PLIγ inhibited enzymatic, inflammatory, and antibacterial activities of snake venom PLA2 isolated from Agkistrodon acutus.