Analysis of a model virus using residue-specific chemical cleavage and MALDI-TOF mass spectrometry.

A nonenzymatic proteomics strategy is applied to the rapid identification of viruses. The approach provides solubilization and subsequent digestion of viral coat proteins in under 30 s. Acid digestions were carried out using a laboratory-quality microwave system equipped with temperature, pressure, and power controls, which allowed for precise optimization of experimental parameters. Under optimal conditions, this method provides an efficient alternative to traditional enzymatic digestion-based methods for virus identification. Following rapid microwave heating of a suspension of a model virus, RNA bacteriophage MS2, 13 chemical digestion products were detected in parallel with the coat protein precursor using MALDI-TOF MS. Because of the high sequence coverage obtained, the bacteriophage MS2 coat protein was identified with high confidence and the specificity of the identification allowed for the discrimination between bacteriophage MS2 and other closely related RNA bacteriophages.