Viral proteomics: The emerging cutting-edge of virus research

Zhou, ShengTao; Liu, Rui; Zhao, Xia; Huang, CanHua; Wei, YuQuan

In 2004, Zeng et al. [20] utilized one-dimensional electrophoresis followed by ESI MS/MS identification or a shotgun strategy with two-dimensional liquid chromatography-ESI MS/MS to identify the structural proteins of SARS coronavirus (SARS-CoV) isolated from Vero E6 cells infected with the BJ-01 strain of the virus. All four of the predicted structural proteins (nucleocapsid (N), spike (S), membrane (M), and envelope (E)) were identified, and a novel phosphorylated site of the M protein was revealed. This combination of gel-based and non-gel approaches provides a fast and complimentary tool, which can be expected to be widely applied in the analysis of other viruses. An-other comprehensive proteomic analysis on the structural proteins of SARS-CoV uncovered three of the structural proteins (S, N, and M). Four glycosylation sites of the S protein were discovered by comparing the mass spectra before and after deglycosylation of the peptides with PNGase F digestion. Surprisingly, a number of shorter isoforms of the N protein were noted by SDS-PAGE and identified by mass spectrometry characterization [30] . This study suggested that the identification of virus-specific proteins by MS could be effectively employed as a diagnostic method for rapid screening of highly infectious viruses, virus-infected cells, or even biofluids containing viruses.