Juvenile hormone binding protein and transferrin from Galleria mellonella share a similar structural motif

It has been previously suggested that juvenile hormone binding protein(s) ( JHBP) belongs to a new class of proteins. In the search for other protein(s ) that may contain structural motifs similar to those found in JHBP, hemoly mph from Galleria mellonella (Lepidoptera) was chromatographed over a Sepha dex G-200 column and resulting fractions were subjected to SDS-PAGE, transf erred onto nitrocellulose membrane and scanned with a monoclonal antibody, mAb 104, against hemolymph JHBP. Two proteins yielded a positive reaction w ith mAb 104, one corresponding to JHBP and the second corresponding to a tr ansferrin, as judged from N-terminal amino acid sequencing (KPNYKIXVPQKFLKE XEQMLEVXT) and Ferene S staining. Transferrin was purified to about 80% hom ogeneity using a two-step procedure including Sephadex G-200 gel filtration and HPLC MonoQ column chromatography. Panning of a random peptide display library and analysis with immobilized synthetic peptides were applied for f inding a common epitope present in JHBP and the transferrin molecule. The p ostulated epitope motif recognized by mAb 104 in the JHBP sequence is RDTKA VN, and is localized at position 82-88.