REMARKS ON THE PHYLOGENY AND STRUCTURE OF FATTY-ACID-BINDING PROTEINSFROM PARASITIC PLATYHELMINTHS

Four fatty acid binding proteins (FABPs) have been described in 4 para sitic platyhelminths: Schistosoma mansoni, Schistosoma japonicum, Fasc iola hepatica and Echinococcus granulosus. FABPs form a multigenic fam ily of cytosolic proteins widely distributed in metazoan tissues, the function of which is still poorly understood. These helminth proteins have recently received attention, since there are reports to indicate that S. mansoni and F. hepatica FABPs may be protective antigens. In a ddition, these proteins could play a major role in the parasites' life -cycles because platyhelminths are unable to synthesize de novo most o f their lipids, We have undertaken phylogenetic and structural analyse s of platyhelminth FABPs in an attempt to characterize features of bio logical relevance. Phylogenetically, these FABPs appear to be more clo sely related to those of vertebrate heart, mammary gland, muscle, reti na, skin, brain and myelin, although no clear functional relationships mere established between them, We describe several conserved motifs c haracteristic of specific groups of FABPs. Hydrophilicity, flexibility and accessibility analyses revealed several major putative epitopes f or the E. granulosus FABP, EgDf1, that appear to be centred in loops o f the EgDf1 3-dimensional structure modelled by molecular replacement. (C) 1997 Australian Society for Parasitology. Published by Elsevier S cience Ltd.