THE OVARY OF THE DESERT LOCUST SCHISTOCERCA-GREGARIA CONTAINS A GLYCINE-RICH AND PROLINE-RICH PEPTIDE THAT DISPLAYS SEQUENCE SIMILARITIES WITH A NEW CLASS OF GPRP PROTEINS FROM PLANTS

A novel, highly hydrophobic, glycine-and proline-rich peptide was char acterized in the ovary of the desert locust, Schistocerca gregaria. Th e peptide was detected as one of the major peaks in a chromatographic separation of an acidic methanolic extract of 50 mature ovaries. Elect rospray mass spectrometry yielded a molecular mass of 6305 Da. The par tial amino acid sequence as determined by Edman degradation based auto mated microsequencing is as follows: a-Arg-Val-Gly-Gly-Tyr-Pro-Ser-Tyr -Gly-Tyr-Pro-Ala. Four amino acids (Gly, Pro, Ala, and Tyr) account fo r more than 80% of the composition of this sequence. Gly-Tyr-Pro is th e most important repetitive motif. Ala-Tyr-Pro, Gly-Tyr-Gly and Gly-Ty r-Ala occur as variations of this motif. The novel glycine-and proline -rich insect peptide displays structural characteristics similar to th ose of a new class of glycine-and proline-rich proteins (GPRP) that ha ve recently been identified in Arabidopsis thaliana (thale cress) and Daucus carota (carrot). The GPRP of A. thaliana contains the same repe titive motifs (except for Ala-Tyr-Pro), the Gly-Tyr-Pro motif also bei ng the most abundant. (C) 1998 Academic Press.