Proteome Analysis to Assess Physiological Changes in Escherichia coli Grown Under Glucose-Limited Fed-Batch Conditions

Abstract

Proteome analysis was used to compare global protein expression changes in Escherichia coli fermentation between exponential and glucose-limited fed-batch phase. Two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry were used to separate and identify 49 proteins showing>2-fold difference in expression. Proteins up regulated during exponential phase include ribonucleotide biosynthesis enzymes and ribosomal recycling factor. Proteins up regulated during fed-batch phase include those involved in high-affinity glucose uptake, transport and degradation of alternate carbon sources and TCA cycle, suggesting an enhanced role of the cycle under glucose- and energy-limited conditions. We report the up regulation of several putative proteins (ytfQ,ygiS,ynaF,yggX,yfeX), not identified in any previous study under carbon-limited conditions.