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The polymerase activity of a mycobacterial galactofuranosyltransferase suggests a novel mechanism for template‐independent processive polymerization
Author(s) -
May John F,
Splain Rebecca A,
Brotschi Christine,
Kiessling Laura L
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1059.2
Subject(s) - galactan , polymerase , biogenesis , polymerization , biochemistry , chemistry , mycobacterium tuberculosis , polysaccharide , biology , enzyme , tuberculosis , polymer , medicine , gene , organic chemistry , pathology
Galactofuranose residues form the structurally crucial galactan polysaccharide in the cell‐wall core of Mycobacterium tuberculosis , the causative agent of tuberculosis. Elucidating galactan biogenesis will help efforts to fight drug‐resistant tuberculosis by providing new therapeutic targets. The mycobacterial galactofuranosyltransferase GlfT is thought to polymerize the galactan, but it is unknown whether GlfT has polymerase activity. Since galactan is built upon a lipid‐linked acceptor, we tested whether the lipid portion of the acceptor influences the activity of GlfT. We found that GlfT processively elongated synthetic acceptors that contained long lipids to produce polysaccharides as long as the naturally occurring galactan. We also found that the degree of polymerization by GlfT depended on acceptor substrate concentration. Our results suggest that GlfT, a template‐independent polymerase, uses a novel mechanism to attain processive polymerization and to control polymeric length. This research was supported by the National Institutes of Health (AI063596); JFM was supported by an National Science Foundation Graduate Research Fellowship.