Molecular analysis of the malR gene of Clostridium butyricum NCIMB 7423, a member of the LacI-GalR family of repressor proteins.
Deletion of a region of DNA 5' to a previously characterised malQ gene of Clostridium butyricum resulted in increased production of the enzyme activity encoded by malQ, 4-alpha-glucanotransferase. Nucleotide sequence analysis revealed the presence of an open reading frame capable of encoding a protein of 335 amino acids. This protein was found to share 33% amino acid sequence identity with the Bacillus subtilis CcpA (catabolite control protein) repressor, 28% identity with the Streptomyces coelicolor MalR repressor, and 30%, 25%, and 21% amino acid identity with the Escherichia coli repressors GalR, LacI and MalI, respectively. The amino-terminal domain was predicted to be able to form a helix-turn-helix structure, and shared highest similarity with the equivalent functional domain from the E. coli LacI repressor. Interruption of malR by the generation of a frameshift mutation led to a 10-fold increase in MalQ activity. These data suggest that the identified open reading frame encodes a repressor of the C. butyricum malQ gene, and of the adjacent malP gene. The gene has, therefore, been designated malR, and its encoded gene product MalR.
Goda
S K
SK
Centre for Applied Microbiology and Research, Salisbury, UK. sayed.goda@camr.org.uk
Eisa
O
O
Akhter
M
M
Minton
N P
NP
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics; D001426:Bacterial Proteins / Q000032:analysis; D003001:Cloning, Molecular; D003013:Clostridium / Q000201:enzymology / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005809:Genes, Regulator / Q000235:genetics*; D006004:Glycogen Debranching Enzyme System / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000235:genetics; D014169:Transformation, Bacterial
D001426:Bacterial Proteins; D006004:Glycogen Debranching Enzyme System; C114295:MalR protein, Clostridium; D012097:Repressor Proteins; C020569:4 alpha-glucanotransferase