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Characterization of D‐arabinosyltransferase activity involved in mycobacterial arabinan biosynthesis using specific synthetic acceptors
Author(s) -
Zhang Jian,
Crick Dean,
Chatterjee Delphi
Publication year - 2006
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.20.5.lb56-d
Subject(s) - biosynthesis , mycobacterium smegmatis , cell wall , chemistry , biochemistry , glycan , glycosyltransferase , pyrophosphate , stereochemistry , enzyme , mycobacterium tuberculosis , medicine , tuberculosis , pathology , glycoprotein
The D‐arabinans in Mycobacterium are essential, extraordinarily complex molecule comprised of D‐arabinofuranose residues which are rarely found in nature. Mycobacterium smegmatis mc 2 155 (WT) was used as a model to study the biosynthesis of cell wall arabinofuran and to define the functions of the membrane bound Emb proteins which are putative arabinosyltransferases. Various arabinosyltransferase assays have been conducted using linkage specific synthetic acceptors such as Araβ1→2Araα1→5Araα1→5Araα1→5Araα1→ with an octyl agycon. In a typical experiment, the acceptor was treated with membrane and cell wall fraction (P‐60) in the presence of [ 14 C] labeled arabinosyl donor, phosphoribose pyrophosphate (pRpp). After work up and analysis, the autoradiography TLC indicated the formation of radioactive compounds migrating slower than the starting material and absent in control (without acceptor) reactions. Detailed studies of the de novo product unequivocally show that two arabinofuranosyl residues are added at the tertiary →5Araα1→ of the synthetic glycan. We believe the work would be able to unravel some aspects of the arabinan biosynthesis of AG and LAM, which may eventually lead to new antituberculosis drug targets. Research supported by NIH/NIAID AI37139