Escherichia coli--a model system that benefits from and contributes to the evolution of proteomics

The large body of knowledge about Escherichia coli makes it a useful model organism for the expression of heterologous proteins. Proteomic studies have helped to elucidate the complex cellular responses of E. coli and facilitated its use in a variety of biotechnology applications. Knowledge of basic cellular processes provides the means for better control of heterologous protein expression. Beyond such important applications, E. coli is an ideal organism for testing new analytical technologies because of the extensive knowledge base available about the organism. For example, improved technology for characterization of unknown proteins using mass spectrometry has made two-dimensional electrophoresis (2DE) studies more useful and more rewarding, and much of the initial testing of novel protocols is based on well-studied samples derived from E. coli. These techniques have facilitated the construction of more accurate 2DE maps. In this review, we present work that led to the 2DE databases, including a new map based on tandem time-of-flight (TOF) mass spectrometry (MS); describe cellular responses relevant to biotechnology applications; and discuss some emerging proteomic techniques.