The Bacillus subtilis crh Gene Encodes a HPr-Like Protein Involved in Carbon Catabolite Repression

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 94; no. 16; pp. 8439 - 8444
• Main Authors: Galinier, Anne, Haiech, Jacques, Kilhoffer, Marie-Claude, Jaquinod, Michel, Stulke, Jorg, Deutscher, Josef, Martin-Verstraete, Isabelle
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 05.08.1997; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences of the USA
• Subjects: Amino Acid Sequence; Amino acids; Bacillus subtilis; Bacillus subtilis - genetics; Bacillus subtilis - metabolism; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biochemistry; Biological Sciences; Carbon - metabolism; Dehydrogenases; DNA; Enzymes; Genes; Genes, Bacterial; Inositols; Life Sciences; Microbiology and Parasitology; Molecular Sequence Data; Mutation; Operons; Phosphoenolpyruvate Sugar Phosphotransferase System - genetics; Phosphoenolpyruvate Sugar Phosphotransferase System - metabolism; Phosphoproteins - genetics; Phosphoproteins - metabolism; Phosphorylation; Plasmids; Proteins; Repression
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.16.8439

Carbon catabolite repression (CCR) of several Bacillus subtilis catabolic genes is mediated by ATP-dependent phosphorylation of histidine-containing protein (HPr), a phosphocarrier protein of the phosphoenolpyruvate (PEP): sugar phosphotransferase system. In this study, we report the discovery of a new B. subtilis gene encoding a HPr-like protein, Crh (for catabolite repression HPr), composed of 85 amino acids. Crh exhibits 45% sequence identity with HPr, but the active site His-15 of HPr is replaced with a glutamine in Crh. Crh is therefore not phosphorylated by PEP and enzyme I, but is phosphorylated by ATP and the HPr kinase in the presence of fructose-1,6-bisphosphate. We determined Ser-46 as the site of phosphorylation in Crh by carrying out mass spectrometry with peptides obtained by tryptic digestion or CNBr cleavage. In a B. subtilis ptsH1 mutant strain, synthesis of β -xylosidase, inositol dehydrogenase, and levanase was only partially relieved from CCR. Additional disruption of the crh gene caused almost complete relief from CCR. In a ptsH1 crh1 mutant, producing HPr and Crh in which Ser-46 is replaced with a nonphosphorylatable alanyl residue, expression of β -xylosidase was also completely relieved from glucose repression. These results suggest that CCR of certain catabolic operons requires, in addition to CcpA, ATP-dependent phosphorylation of Crh, and HPr at Ser-46.