Browse by author
Lookup NU author(s): Dr Laurent Kremer, Dr Lynn Dover, Professor Del Besra
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
The cell wall of Mycobacterium tuberculosis and related genera is unique among prokaryotes, consisting of a covalently bound complex of mycolic acids, D-arabinan and D-galactan, which is linked to peptidoglycan via a special linkage unit consisting of Rhap-(1→3)-GlcNAc-P. Information concerning the biosynthesis of this entire polymer is now emerging with the promise of new drug targets against tuberculosis. Accordingly, we have developed a galactosyltransferase assay that utilizes the disaccharide neoglycolipid acceptors β-D-Galf-(1→5)-β-D-Galf-O-C10:1 and β-D-Galf-(1→6)-β-D-Galf-O-C10:1, with UDP-Gal in conjunction with isolated membranes. Chemical analysis of the subsequent reaction products established that the enzymatically synthesized products contained both β-D-Galf linkages ((1→5) and (1→6)) found within the mycobacterial cell, as well as in an alternating (1→5) and (1→6) fashion consistent with the established structure of the cell wall. Furthermore, through a detailed examination of the M. tuberculosis genome, we have shown that the gene product of Rv3808c, now termed glfF, is a novel UDP-galactofuranosyltransferase. This enzyme possesses dual functionality in performing both (1→5) and (1→6) galactofuranosyltransferase reactions with the above neoglycolipid acceptors, using membranes isolated from the heterologous host Escherichia coli expressing Rv3808c. Thus, at a biochemical and genetic level, the polymerization of the galactan region of the mycolyl-arabinogalactan complex has been defined, allowing the possibility of further studies toward substrate recognition and catalysis and assay development. Ultimately, this may also lead to a more rational approach to drug design to be explored in the context of mycobacterial infections.
Author(s): Kremer L, Dover LG, Morehouse C, Hitchin P, Everett M, Morris HR, Dell A, Brennan PJ, McNeil MR, Flaherty C, Duncan K, Besra GS
Publication type: Article
Publication status: Published
Journal: Journal of Biological Chemistry
Year: 2001
Volume: 276
Issue: 28
Pages: 26430-26440
ISSN (print): 0021-9258
ISSN (electronic): 1083-351X
Publisher: American Society for Biochemistry and Molecular Biology
URL: http://dx.doi.org/10.1074/jbc.M102022200
DOI: 10.1074/jbc.M102022200
PubMed id: 11304545
Altmetrics provided by Altmetric