[Comparative proteomics research on removing of large invasive plasmid pINV of Shigella flexneri 2a strain 2457T]

Abstract

S. flexneri 2a strain 2457T and its derivative without large invasive plasmid pINV-2457T were cultured to middle logarithm phase. Whole cellular protein extracts of the two strains were examined by two dimensional (2D) electrophoresis using immobilized pH gradient (IPG) technology. After in-gel protein digestion, the different-expressed spots were detected by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI TOF MS). All the peptide mass fingerprints (PMFs) were searched by the program Mascot developed by Matrix Science Ltd. For identifying proteins, databases of S. flexneri 2a 2457T was used. Ten proteins with changed expression level were found. Results indicate that expression levels of several enzymes involved in nucleic acid metabolism have risen, and expression increase of deoxycytidine deaminase, purine nucleoside phosphorylase, and uridine nucleoside phosphorylase might lead to increase of uridine and uridine nucleoside synthesization.