Towards a phosphoproteome map of Corynebacterium glutamicum

In this study, the phosphoproteome of Corynebacterium glutamicum, an industrially important soil bacterium of the Corynebacterium/Mycobacterium/Nocardia (CMN) group of Gram-positive bacteria, was investigated by two different detection methods: first, by in vivo radio-labeling using [P-33]-phosphoric acid with subsequent autoradiography and second, by immunostaining with phosphoamino acid-specific monoclonal antibodies. After two-dimensional gel electrophoresis (2-DE), around 60 [P-33]-labeled protein spots were visualized and around 90 antibody-decorated protein spots detected; 31 of the protein spots were detected with both methods. By peptide mass fingerprinting, 41 different proteins were identified, namely 5-enolpyruvylshikimate 3-phosphate synthase, aconitase, acyl-CoA carboxylase, acyl-CoA synthetase, ATP (synthase alpha- and beta-chain), carbamoyl-phosphate synthase, citrate synthase, cysteine synthase, DnaK, the elongation factors G, P, Ts and Tu, enolase, fructose bisphosphate aldolase, fumarase, Gap dehydrogenase, glutamine synthetase I, glycine hydroxymethyltransferase, GroEL2, GTPase, heat-inducible transcriptional repressor DnaJ2, inorganic pyrophosphatase, isocitrate dehydrogenase, ketol-acid reductoisomerase, lactate dehydrogenase, leucine-tRNA ligase, lipoamide dehydrogenase, methionine synthase, O-acetylhomoserine sulfhydrylase, pyruvate carboxylase, pyruvate kinase, pyruvate oxidase, ribosomal protein S1, RNA polymerase (beta-subunit), succinyl-CoA:CoA transferase, transketolase and UDP-N-acetylmuramyl-L-alanine ligase, besides a hypothetical 35k protein and a hypothetical glucose kinase. Both detection techniques were used to create a phosphoproteome map. Additionally, the influence of nitrogen deprivation on the phosphoproteome of C. glutamicum was investigated.