Venom from the centipede Scolopendra viridis Say: Purification, gene cloning and phylogenetic analysis of a phospholipase A2

Abstract

Venom components from the centipede Scolopendra viridis Say were studied, using both the soluble venom and a cDNA library prepared from mRNA of the venomous glands. Separation of the soluble venom by high performance liquid chromatography (HPLC) permitted to obtain at least 54 different fractions. The fraction eluting at 46.24 min showed phospholipase activity. The enzyme was purified to homogeneity and the first 25 amino acid residues were identified by Edman degradation. From the cDNA library several genes were cloned, one of which codes for a protein with identical amino acid sequence as the one experimentally determined. The cloned gene codes for a signal peptide of 28 amino acids and a mature peptide of 119 residues. The molecular weight of the enzyme was estimated by mass spectrometry and shown to be 13,752 Da, which matches exactly with the molecular mass expected from the deduced amino acid sequence of the gene. Phylogenetic analysis of this sequence, in comparison with other known from venomous animals, showed that it is more similar to snake phospholipases than to insect or arachnid sequences, suggesting that it has been submitted to convergent evolution. To the best of our knowledge this is the first time that a phospholipase from this species of animal is fully characterized. We have named it Scol/Pla.