Sarcophagid larval proteins: partial sequence homologies among three cuticle proteins and related structures of...

Three structural proteins from the larval cuticle of Sarcophaga bullata have been sequenced at the amino terminus for 30-40 residues. We observed a high degree of homology with related proteins of Drosophila melanogaster, based on the previous findings of M. Snyder, J. Hirsh, and N. Davidson [(1981) Cell 25:165-177]. S. bullata protein SC1 had 65% homology with Drosophila isolate CP1, and SC6 showed 49% homology with CPX and 54% with CP2a. The three sarcophagid polypeptides also resembled each other with respect to mapped products of tryptic cleavage. The sites of posttranslational arylation required for puparium formation, namely histidyl and lysyl residues, were asymmetrically distributed in the sarcophagid samples. In SC1 the bulk of the loci of putative crosslinks lay beyond the 43-residue fragment. In SC6 half the histidines fell within the first 25% of the primary chain.