title: Isolation and characterisation of an aryl-beta-D-glucoside uptake and utilisation system (abg) from the gram-positive ruminal Clostridium species C. longisporum.
abstract: A phosphotransferase-dependent aryl-beta-glucoside uptake and utilisation system (abg) was isolated from the ruminal Clostridium ("C. Longisporum"). The system is composed of three genes, abgG, abgF and abgA, and a number of regulatory regions, including terminator/antiterminator type stem-loop structures preceding the abgG and abgF genes. Similarity analysis of the proteins encoded by these genes indicated that they were responsible for the regulation of the abg system through antitermination (AbgG), the uptake and phosphorylation of aryl-beta-glucosides (AbgF) and the hydrolysis of the intracellular phosphorylated glycosides (AbgA). Experimental evidence for the functions of AbgF and AbgA was obtained. Although it was not possible to demonstrate any function for AbgG, a promoter 5' to the abgG gene was identified which was responsible for expression of the downstream genes. The abg system is remarkably similar to operons from the gram negative Enterobacteriaceae, both in the coding and non-coding regulatory regions.
authors.affiliation: Department of Microbiology, University of Cape Town, South Africa.
authors.forename: G D
authors.initials: GD
authors.lastname: Brown
authors.forename: J A
authors.initials: JA
authors.lastname: Thomson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001104:Arbutin / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D001592:Benzyl Alcohols / Q000378:metabolism; D001692:Biological Transport; D002918:Chymotrypsin / Q000235:genetics*; D003001:Cloning, Molecular; D003013:Clostridium / Q000235:genetics / Q000378:metabolism*; D015723:Gene Library; D005798:Genes, Bacterial; D005960:Glucosides / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000235:genetics*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics*; D010766:Phosphorylation; D012417:Rumen / Q000382:microbiology; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D001592:Benzyl Alcohols; D005960:Glucosides; D026901:Membrane Transport Proteins; D009097:Multienzyme Complexes; C110872:abgF protein, Clostridium longisporum; C110871:abgG protein, Clostridium longisporum; C005696:salicin; D001104:Arbutin; D006026:Glycoside Hydrolases; C110873:abgA protein, Clostridium longisporum; D002918:Chymotrypsin; C023924:alpha mucase