Newly discovered features of the updated sequence of royal jelly protein RJP571;: longer repetitive region on C-terminus and homology to Drosophila melanogaster yellow protein

The previously published nucleotide sequence of complementary DNA (cDNA), coding for royal jelly protein RJP57-I, contained errors that were corrected by resequencing of the cDNA. The main error, the omission of a 108 bp (base pairs) long sequence on the Tend of the cDNA was caused by misalignment of overlapping parts of the sequenced fragments in the region containing repetitive sequences. The updated sequence of RJP57-I cDNA is 1807 bp long and encodes a protein with 544 amino acid residues including the signal peptide. The protein shows sequence homology over 385 residues with the yellow protein of Drosophila melanogaster, which is involved in the process of melanin pigmentation of Drosophila cuticle. The RJP57-I protein sequence possesses a 100 amino acid residues long repetitive region consisting of a 20-fold repeated sequence motif XQNXX on its C-terminal part. The repetitive region is interesting because of the regular distribution of cationic amino acid residues (arginine/lysine) in the last 14 repeats and the non-regular distribution of 10 residues of anionic aspartic acid throughout the whole repetitive region. According to computer analyses, the region possesses a structure of regularly pleated peptide chain. The hydrophilic character of the repetitive region and the supposed specific structure indicate that it could form a distinct structural domain located on the protein surface. The question of the possible function of RJP57-I protein in the honey bee (Apis mellifera) is discussed on the basis of these new findings.