Phospholipases A2: a dendrogram from a distance matrix based on size and hydrophobicity of the residues in their...

A distance matrix was obtained from aligned homologous sequences of 32 phospholipases A2 (EC 3.1.1.4) (24 from Elapid and 5 from Viperid venoms, and 3 from mammals), on the basis of the quantities Dij which are defined from a two-dimensional vector representation of the amino acid residues (dimensions: size and hydrophobicity). These Dij quantities were proposed in a previous paper (Ventura, M. M., (1989), An. Acad. brasil. Ci., 61: 215). A dendrogram was constructed from this distance matrix employing, for cluster analysis, the unweighted pair-group using arithmetic averages. Two groups of phospholipases A2: a) Elapid venom enzymes together with the three mammalian pancreatic enzymes (bovine, equine and porcine), and b) Viper venom enzymes (Crotalus, Trimeresurus and Bitis enzymes) can be well distinguished in the topology of the dendrogram. The Elapid group of enzymes is divided into two subgroups: a) Naja, Hemachatus and Bungarus venom enzymes, and b) Notechis, Laticauda, Enhydrina and Oxyuranus venom enzymes. It is observed that there is a close similarity between the mammalian pancreatic phospholipases A2 and the enzymes from Naja, Hemachatus and Bungarus. These results are similar to those reported by Dufton and Hider (Eur. J. Biochem., 137:545 (1983] which were obtained from the distance matrix based on minimum mutation distance between 25 selected residue positions in the pairwise compared sequences.