Inactivation of the Mycobacterial Rhamnosyltransferase, Which Is Needed for the Formation of the Arabinogalactan-Peptidoglycan Linker, Leads to Irreversible Loss of Viability
Temperature-sensitive mutant 2-20/32 of Mycobacterium smegmatis mc 2 155 was isolated and genetically complemented with a Mycobacterium tuberculosis H37Rv DNA fragment that contained a single open reading frame. This open reading frame is designated Rv3265c in the M. tuberculosis H37Rv genome. Rv326...
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Published in | The Journal of biological chemistry Vol. 279; no. 42; pp. 43540 - 43546 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Society for Biochemistry and Molecular Biology
15.10.2004
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Subjects | |
Online Access | Get full text |
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Summary: | Temperature-sensitive mutant 2-20/32 of Mycobacterium smegmatis mc 2 155 was isolated and genetically complemented with a Mycobacterium tuberculosis H37Rv DNA fragment that contained a single open reading frame. This open reading frame is designated Rv3265c in the M. tuberculosis H37Rv genome. Rv3265c shows homology to the Escherichia coli gene wbbL , which encodes a dTDP-Rha:α- d -GlcNAc-pyrophosphate polyprenol, α-3- l -rhamnosyltransferase. In E. coli this enzyme is involved in O-antigen synthesis, but in mycobacteria it is required for the rhamnosyl-containing linker unit
responsible for the attachment of the cell wall polymer mycolyl-arabinogalactan to the peptidoglycan. The M. tuberculosis wbbL homologue, encoded by Rv3265c, was shown to be capable of restoring an E. coli K12 strain containing an insertionally inactivated wbbL to O-antigen positive. Likewise, the E. coli wbbL gene allowed 2-20/32 to grow at higher non-permissive temperatures. The rhamnosyltransferase activity of M. tuberculosis WbbL was demonstrated in 2-20/32 as was the loss of this transferase activity in 2-20/32 at elevated temperatures. The wbbL of the temperature-sensitive mutant contained a single-base change that converted what was a proline in mc 2 155 to a serine residue. Exposure of 2-20/32 to higher non-permissive temperatures resulted in bacteria that could not be
recovered at the lower permissive temperatures. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.M407782200 |