Isolation and characterisation of an aryl-β-D-glucoside uptake and utilisation system ( abg ) from the gram-positive ruminal Clostridium species C. longisporum |
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Authors: | G D Brown and J A Thomson |
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Institution: | (1) Department of Microbiology, University of Cape Town, PB Rondebosch 7700, South Africa Fax: +27-21-689-7573; e-mail: JAT@molbiol.uct.ac.za, ZA |
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Abstract: | A phosphotransferase-dependent aryl-β-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-β-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.
Received: 3 April 1997 / Accepted: 8 September 1997 |
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Keywords: | Clostridium Aryl-β -glucoside PTS |
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