Proteome analysis of Corynebacterium glutamicum

By the use of different Corynebacterium glutamicum strains more than 1.4 million tons of amino acids, mainly L‐glutamate and L‐lysine, are produced per year. A project was started recently to elucidate the complete DNA sequence of this bacterium. In this communication we describe an approach to analyze the C. glutamicum proteome, based on this genetic information, by a combination of two‐dimensional (2‐D) gel electrophoresis and protein identification via microsequencing or mass spectrometry. We used these techniques to resolve proteins of C. glutamicum with the aim to establish 2‐D protein maps as a tool for basic microbiology and for strain improvement. In order to analyze the C. glutamicum proteome, methods were established to fractionate the C. glutamicum proteins according to functional entities, i.e., cytoplasm, membranes, and cell wall. Protein spots of the cytoplasmic and membrane fraction were identified by N‐terminal sequencing, immunodetection, matrix assisted laser desorption/ionization‐time of flight‐mass spectrometry (MALDI‐TOF‐MS) and electrospray ionization‐mass spectrometry (ESI‐MS). Additionally, a protocol to analyze proteins secreted by C. glutamicum was established. Approximately 40 protein spots were observed on silver‐stained 2‐D gels, 12 of which were identified.