The precursor protein of the structural apolipoproteins of lipophorin: cDNA and deduced amino acid sequence.

A 10 138 bp cDNA from the fat body of the tobacco hornworm, Manduca sexta, which encodes the precursor protein for apolipophorin aPOLP-1 and -II, the structural apolipoproteins of the insect lipoprotein, lipophorin, has been cloned and sequenced. The cDNA has a single 9915 bp open reading frame beginning at an initiating ATG at bp 59 and extending to a stop codon at position 9974. This open reading frame encodes a 3305 amino acid protein with a molecular mass of 366 812 Da. Signal peptide cleavage is predicted to occur after residue 23, leaving a 3,282 amino acid precursor protein. The precursor protein is arranged with apoLp-II at the amino terminal end and apoLp-I at the carboxy terminal end. At present, the site of cleavage of the precursor protein to generate apoLp-I and -II is unknown.