Conformational properties of phospholipases A2. Secondary-structure prediction, circular dichroism and relative interface hydrophobicity.

The sequences of 32 phospholipases A2 (EC 3.1.1.4) were analysed by secondary-structure prediction and the results were compared with the available crystallographic data. Good agreement is evident between prediction and experiment, especially for helical structure. Circular dichroic spectra were also determined for six enzymes from Elapid snake venom and these, in association with previously published spectra, confirm the main implication of the predictions, namely that all the homologues have qualitatively similar tertiary structures. Consideration was then given to possible structure/activity relationships in the light of the above findings. The relative hydrophobicity/hydrophilicity of the area of the enzyme thought to interact with lipid/water interfaces was predicted and certain correlations were noted with relative penetrating power, species of origin and the presence of beta-neurotoxic properties.