Linked Life Data

21030587

Source:http://linkedlifedata.com/resource/pubmed/id/21030587

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
53
pubmed:dateCreated
2010-12-27
pubmed:abstractText
The arabinogalactan (AG) of slow growing pathogenic Mycobacterium spp. is characterized by the presence of galactosamine (GalN) modifying some of the interior branched arabinosyl residues. The biosynthetic origin of this substituent and its role(s) in the physiology and/or pathogenicity of mycobacteria are not known. We report on the discovery of a polyprenyl-phospho-N-acetylgalactosaminyl synthase (PpgS) and the glycosyltransferase Rv3779 from Mycobacterium tuberculosis required, respectively, for providing and transferring the GalN substrate for the modification of AG. Disruption of either ppgS (Rv3631) or Rv3779 totally abolished the synthesis of the GalN substituent of AG in M. tuberculosis H37Rv. Conversely, expression of ppgS in Mycobacterium smegmatis conferred upon this species otherwise devoid of ppgS ortholog and any detectable polyprenyl-phospho-N-acetylgalactosaminyl synthase activity the ability to synthesize polyprenyl-phospho-N-acetylgalactosamine (polyprenyl-P-GalNAc) from polyprenyl-P and UDP-GalNAc. Interestingly, this catalytic activity was increased 40-50-fold by co-expressing Rv3632, the encoding gene of a small membrane protein apparently co-transcribed with ppgS in M. tuberculosis H37Rv. The discovery of this novel lipid-linked sugar donor and the involvement of a the glycosyltransferase C-type glycosyltransferase in its transfer onto its final acceptor suggest that pathogenic mycobacteria modify AG on the periplasmic side of the plasma membrane. The availability of a ppgS knock-out mutant of M. tuberculosis provides unique opportunities to investigate the physiological function of the GalN substituent and the potential impact it may have on host-pathogen interactions.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
31
pubmed:volume
285
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
41348-55
pubmed:dateRevised
2011-3-14
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Biosynthetic origin of the galactosamine substituent of Arabinogalactan in Mycobacterium tuberculosis.
pubmed:affiliation
Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural