NMR Analysis of a Stress Response Metabolic Signaling Network

Authors

Bo Zhang, University of Nebraska-LincolnFollow
Steven M. Halouska, University of Nebraska-LincolnFollow
Charles E. Schiaffo, University of Nebraska-Lincoln
Marat R. Sadykov, University of Nebraska-Lincoln
Greg A. Somerville, University of Nebraska - LincolnFollow
Robert Powers, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2011

Citation

J Proteome Res. 2011 August 5; 10(8): 3743–3754. doi:10.1021/pr200360w.

Comments

© 2011 American Chemical Society

Abstract

We previously hypothesized that Staphylococcus epidermidis senses a diverse set of environmental and nutritional factors associated with biofilm formation through a modulation in the activity of the tricarboxylic acid (TCA) cycle. Herein, we report our further investigation of the impact of additional environmental stress factors on TCA cycle activity and provide a detailed description of our NMR methodology. S. epidermidis wild-type strain 1457 was treated with stressors that are associated with biofilm formation, a sub-lethal dose of tetracycline, 5% NaCl, 2% glucose and autoinducer-2 (AI-2). As controls and to integrate our current data with our previous study, 4% ethanol stress and iron-limitation were also used. Consistent with our prior observations, the effect of many environmental stress factors on the S. epidermidis metabolome was essentially identical to the effect of TCA cycle inactivation in the aconitase mutant strain 1457-acnA::tetM. A detailed quantitative analysis of metabolite concentration changes using 2D ¹H-¹³C HSQC and ¹H-¹H TOCSY spectra identified a network of 37 metabolites uniformly affected by the stressors and TCA cycle inactivation. We postulate that the TCA cycle acts as the central pathway in a metabolic signaling network.