Top-down proteomics reveals a unique protein S-thiolation switch in Salmonella Typhimurium in response to infection-like conditions

Charles Ansong, Si Wu, Da Meng, Xiaowen Liu, Heather M. Brewer, Brooke L.Deatherage Kaiser, Ernesto S. Nakayasu, John R. Cort, Pavel Pevzner, Richard D. Smith, Fred Heffron, Joshua N. Adkins, Ljiljana Paša-Tolić

Research output: Contribution to journalArticlepeer-review

124 Scopus citations


Characterization of the mature protein complement in cells is crucial for a better understanding of cellular processes on a systemswide scale. Toward this end, we used single-dimension ultra-highpressure liquid chromatography mass spectrometry to investigate the comprehensive "intact" proteome of the Gram-negative bacterial pathogen Salmonella Typhimurium. Top-down proteomics analysis revealed 563 unique proteins including 1,665 proteoforms generated by posttranslational modifications (PTMs), representing the largest microbial top-down dataset reported to date. We confirmed many previously recognized aspects of Salmonella biology and bacterial PTMs, and our analysis also revealed several additional biological insights. Of particular interest was differential utilization of the protein S-thiolation forms S-glutathionylation and S-cysteinylation in response to infection-like conditions versus basal conditions. This finding of a S-glutathionylation-to-S-cysteinylation switch in a condition-specific manner was corroborated by bottom-up proteomics data and further by changes in corresponding biosynthetic pathways under infection-like conditions and during actual infection of host cells. This differential utilization highlights underlying metabolic mechanisms that modulate changes in cellular signaling, and represents a report of S-cysteinylation in Gram-negative bacteria. Additionally, the functional relevance of these PTMs was supported by protein structure and gene deletion analyses. The demonstrated utility of our simple proteome-wide intact protein level measurement strategy for gaining biological insight should promote broader adoption and applications of top-down proteomics approaches.

Original languageEnglish (US)
Pages (from-to)10153-10158
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number25
StatePublished - Jun 18 2013
Externally publishedYes

ASJC Scopus subject areas

  • General


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