PBP FROM SCARAB BEETLES REPRESENT THE MOST WIDELY DISTRIBUTEDCLASS OF PROTEINS IN INSECTS.

Hubert Wojtasek and Walter S. Leal
Laboratory of Chemical Prospecting, National Institute of Sericulturaland Entomological Science, 1-2 Ohwashi, Tsukuba 305, Japan.

We have characterized putative odorant/pheromone binding proteins intwo scarab beetles: Anomala osakana and Popillia japonica that utilize opposite enantiomers of (Z)-5-(1-decenyl)oxacyclopentan-2-oneas their pheromones. In both species there was only one antennae-specificprotein which was present in both sexes. These proteins bound radiolabeledpheromones very weakly and discrimination between ligands could not bedemonstrated. Unexpectedly, these ligands were bound by PBPs frommoth species, Manduca sexta and Samia cynthia ricini, whichutilize aldehydes as their pheromones, casting doubt on high ligand specificitypostulated for this class of proteins. We cloned these PBP from bothA. osakana and P. japonica. Their amino acidsequences were highly conserved between these two species (90% identityand 97% similarity). These proteins also showed considerable homology(30-36% identity) to putative OBPs from D. melanogaster, Bombyxmori (ABPX protein) and Lygus lineolaris but nosimilarity with classical PBPs from Lepidoptera.