Nicole Dusch

The complete Corynebacterium glutamicum ATCC 13032 genome sequence and its impact on the production of l-aspartate-derived amino acids and vitamins

The complete genomic sequence of Corynebacterium glutamicum ATCC 13032, well-known in industry for the production of amino acids, e.g. of L-glutamate and L-lysine was determined. The C. glutamicum genome was found to consist of a single circular chromosome comprising 3282708 base pairs. Several DNA regions of unusual composition were identified that were potentially acquired by horizontal gene transfer, e.g. a segment of DNA from C. diphtheriae and a prophage-containing region. After automated and manual annotation, 3002 protein-coding genes have been identified, and to 2489 of these, functions were assigned by homologies to known proteins. These analyses confirm the taxonomic position of C. glutamicum as related to Mycobacteria and show a broad metabolic diversity as expected for a bacterium living in the soil. As an example for biotechnological application the complete genome sequence was used to reconstruct the metabolic flow of carbon into a number of industrially important products derived from the amino acid L-aspartate.

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.