Application of nanoLC–MS/MS to the shotgun proteomic analysis of the nematocyst proteins from jellyfish Stomolophus meleagris

The nematocyst proteins of jellyfish Stomolophus meleagris, a complicated mixture, contain many important bioactive molecules. In present study, to gain comprehensive insight into the protein component and search some novel bioactive molecules in the nematocyst proteins, shotgun proteomic analysis of the nematocyst proteins was carried out by nano liquid chromatography tandem mass spectrometry (nanoLC–MS/MS) for the first time. Digested peptides of the nematocyst proteins were analyzed by nanoLC–MS/MS and all MS/MS spectra were then automatically searched by the SEQUEST program. A total of 181 proteins had been identified, with the molecular weight ranging from 5268.06 to 843,487.57 and the pI from 4.49 to 11.39. Bioinformatic analysis was also applied to better understand the identified proteins. In the gene ontology (GO) annotation, all the identified proteins were classified into 13, 9 and 7 groups according to biological process, cellular component and molecular function, respectively. Pathways analysis of the identified proteins was conducted with 33 corresponding pathways found. On the basis of pathways analysis, we also constructed the gene network to analyze the relationship of those genes each other, which contained enzyme–enzyme relation, protein–protein interaction and gene expression interaction.