The amrG1 gene is involved in the activation of acetate in Corynebacterium glutamicum.
During growth of Corynebacterium glutamicum on acetate as its carbon and energy source, the expression of the pta-ack operon is induced, coding for the acetate-activating enzymes, which are phosphotransacetylase (PTA) and acetate kinase (AK). By transposon rescue, we identified the two genes amrG1 and amrG2 found in the deregulated transposon mutant C. glutamicum G25. The amrG1 gene (NCBI-accession: AF532964) has a size of 732 bp, encoding a polypeptide of 243 amino acids and apparently is partially responsible for the regulation of acetate metabolism in C. glutamicum. We constructed an in-frame deletion mutant and an over-expressing strain of amrG1 in the C. glutamicum ATCC13032 wildtype. The strains were then analyzed with respect to their enzyme activities of PTA and AK during growth on glucose, acetate and glucose or acetate alone as carbon sources. Compared to the parental strain, the amrG1 deletion mutant showed higher specific AK and PTA activities during growth on glucose but showed the same high specific activities of AK and PTA on medium containing acetate plus glucose and on medium containing acetate. In contrast to the gene deletion, overexpression of the amrG1 gene in C. glutamicum 13032 had the adverse regulatory effect. These results indicate that the amrG1 gene encodes a repressor or co-repressor of the pta-ack operon.
Ruan
Hong
H
Department of Biology, Zhejiang University City College, Hangzhou 310015, China. ruanhong@yahoo.com
Gerstmeir
R
R
Schnicke
S
S
Eikmanns
B J
BJ
D000084:Acetate Kinase / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000085:Acetates / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005798:Genes, Bacterial; D005947:Glucose / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009876:Operon; D010709:Phosphate Acetyltransferase / Q000032:analysis / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D000085:Acetates; D003470:Culture Media; D010709:Phosphate Acetyltransferase; D000084:Acetate Kinase; D005947:Glucose