关键词: 小菜蛾, 蛋白质, 肽质量指纹图谱, 串联质谱, de novo测序, 生物信息学

Abstract: Protein expression in different larval instars of the diamondback moth (DBM), Plutella xylostella, was characterized by two dimensional gel electrophoresis (2-DE). Twenty-four differentially expressed protein spots were discriminated. The spot 1111 was selected for peptide mass fingerprinting (PMF) and peptide sequence using matrix-assisted laser desorption ionization of time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS). The PMF was used to search for the matched protein based on NCBInr Metazoa database with MASCOT and ProFound softwares, but the match was unsatisfied. The PMF+MS/MS spectrum was further used to search for the matched protein, and the protein was identified as GA18218-PA of Drosophila pseudoobscura based on the NCBInr Metazoa database while it was identified as the subunit d of H⁺ transporting ATP synthase of Bombyx mori based on the EST database of DBM population. To validate the result of matching, the spot was used for chemical N-terminal derivatization of the tryptic peptides with 4-sulfophenyl isothiocyanate (SPITC) prior to MALDI-TOF/TOF MS, and the protein was identified as a subunit of ATP synthase again. Finally, potential application of MS analysis and bioinformatics as tools to select the optimal method in proteomic research on non-model insects was discussed in some detail.

Key words: Plutella xylostella, protein, peptide mass fingerprinting, tandem mass spectrometry, bioinformatics