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Updated: Jun 4, 2026
A Tandem Liquid Chromatography–Mass Spectrometry-based Approach for Metabolite Analysis of Staphylococcus aureus
Published on: March 28, 2017
Quantitative proteomic view on secreted, cell surface-associated, and cytoplasmic proteins of the
Kristina Hempel1, Florian-Alexander Herbst, Martin Moche
1Institute for Microbiology, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany.
Abstract:
Staphylococcus aureus is capable of colonizing and infecting humans by its arsenal of surface-exposed and secreted proteins. Iron-limited conditions in mammalian body fluids serve as a major environmental signal to bacteria to express virulence determinants. Here we present a comprehensive, gel-free, and GeLC-MS/MS-based quantitative proteome profiling of S. aureus under this infection-relevant situation. (14)N(15)N metabolic labeling and three complementing approaches were combined for relative quantitative analyses of surface-associated proteins. The surface-exposed and secreted proteome profiling approaches comprise trypsin shaving, biotinylation, and precipitation of the supernatant. By analysis of the outer subproteomic and cytoplasmic protein fraction, 1210 proteins could be identified including 221 surface-associated proteins. Thus, access was enabled to 70% of the predicted cell wall-associated proteins, 80% of the predicted sortase substrates, two/thirds of lipoproteins and more than 50% of secreted and cytoplasmic proteins. For iron-deficiency, 158 surface-associated proteins were quantified. Twenty-nine proteins were found in altered amounts showing particularly surface-exposed proteins strongly induced, such as the iron-regulated surface determinant proteins IsdA, IsdB, IsdC and IsdD as well as lipid-anchored iron compound-binding proteins. The work presents a crucial subject for understanding S. aureus pathophysiology by the use of methods that allow quantitative surface proteome profiling.
Insights
Staphylococcus aureus alters its surface proteins under iron-limited conditions, crucial for infection. This study quantifies these changes, identifying key iron-regulated surface proteins involved in bacterial virulence.
Area of Science:
- Microbiology
- Proteomics
- Bacterial Pathogenesis
Background:
- Staphylococcus aureus utilizes surface proteins for colonization and infection.
- Bacterial virulence is often regulated by environmental cues, such as iron availability in host environments.
Purpose of the Study:
- To perform a comprehensive, quantitative proteome profiling of S. aureus under iron-limited conditions.
- To identify and quantify changes in surface-associated and secreted proteins during infection-relevant iron scarcity.
Main Methods:
- Utilized gel-free, GeLC-MS/MS-based quantitative proteome profiling.
- Employed (14)N/(15)N metabolic labeling combined with trypsin shaving, biotinylation, and supernatant precipitation for surface protein analysis.
- Analyzed outer subproteomic and cytoplasmic protein fractions.
Main Results:
- Identified 1210 proteins, including 221 surface-associated proteins, providing access to a significant portion of predicted cell wall proteins, sortase substrates, lipoproteins, and secreted/cytoplasmic proteins.
- Quantified 158 surface-associated proteins under iron deficiency.
- Observed altered amounts in 29 proteins, with strong induction of surface-exposed proteins like IsdA, IsdB, IsdC, and IsdD, and lipid-anchored iron-binding proteins.
Conclusions:
- This study provides crucial insights into Staphylococcus aureus pathophysiology by quantitatively profiling its surface proteome under iron-limiting conditions.
- Identified specific surface proteins, particularly iron-regulated ones, that are upregulated during host-relevant iron scarcity, highlighting their role in virulence.
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