Isolation, cloning and deduced amino acid sequence of a novel glycoprotein from the haemolymph of the hawkmoth Manduca sexta.

A low-abundance haemolymph protein from adult male Manduca sexta was purified to homogeneity. The 29,000 Da glycoprotein is synthesized in the fat body, is present in both male and female, and is present during all stages of development. Antiserum against the 29 kDa protein was raised in a rabbit and used to screen an M. sexta larval fat body cDNA library. An 880 base pair clone was isolated and found to contain the full-length transcript. Sequencing of the cDNA revealed an open reading frame of 699 bases beginning from the possible translation initiation site. The deduced 233-amino acid polypeptide contains an apparent 17-amino acid signal peptide and three potential N-glycosylation sites. The function of the 29 kDa protein is unknown.