Analysis of the elements of catabolite repression in Clostridium acetobutylicum ATCC 824.
The PTSH gene, encoding the phosphotransferase protein HPr, from Clostridium acetobutylicum ATCC 824 was identified from the genome sequence, cloned and shown to complement a PTSH mutant of Escherichia coli. The deduced protein sequence shares significant homology with HPr proteins from other low-GC gram-positive bacteria, although the highly conserved sequence surrounding the Ser-46 phosphorylation site is not well preserved in the clostridial protein. Nevertheless, the HPr was phosphorylated in an ATP-dependent manner in cell-free extracts of C. Acetobutylicum. Furthermore, purified His-tagged HPr from Bacillus Subtilis was also a substrate for the clostridial HPr kinase/phosphorylase. This phosphorylation reaction is a key step in the mechanism of carbon catabolite repression proposed to operate in B. Subtilis and other low-GC gram-positive bacteria. Putative genes encoding the HPr kinase/phosphorylase and the other element of this model, namely the catabolite control protein CcpA, were identified from the C. Acetobutylicum genome sequence, suggesting that a similar mechanism of carbon catabolite repression may operate in this industrially important organism.
School of Life Sciences, Napier University, Edinburgh, UK.
Martin
M
Tangney
Anne
A
Galinier
Josef
J
Deutscher
Wilfrid J
WJ
Mitchell
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D003013:Clostridium / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010802:Phylogeny; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; C069286:catabolite control proteins, bacteria; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr