Characterization of the in vitro synthesized arabinan of mycobacterial cell walls.
Previous studies have shown that polymerized [14C]arabinan can be synthesized from polyprenylphosphate-[14C]arabinose by the particulate enzymes of Mycobacterium smegmatis [R.E. Lee, K. Mikusová, P.J. Brennan and G.S Besra (1995) J. Am. Chem. Soc. 117, 11829-11832]. In the present investigation, the [14C]arabinan product was biochemically characterized. Sizing chromatography revealed a molecular weight consistent with that expected from mature arabinan. Digestion of the [14C]arabinan with a mixture of arabinases produced oligo[14C]arabinoside fragments including hexa[14C]arabinoside and tetra[14C]arabinoside which originated from the non-reducing terminal regions of the polymer, and di[14C]arabinoside from the internal regions of the polymer. These arabinoside fragments represent the major known structural motifs that comprise the arabinan segment of arabinogalactan and lipoarabinomannan. The presence of [14C]arabinose in both the internal and external regions of the [14C]arabinan suggests that polyprenylphosphate-arabinose is the major, and perhaps the only, donor of arabinosyl residues in mycobacteria.
Xin
Y
Y
Department of Microbiology, Colorado State University, Fort Collins 80523, USA.
Lee
R E
RE
Scherman
M S
MS
Khoo
K H
KH
Besra
G S
GS
Brennan
P J
PJ
McNeil
M
M
D002473:Cell Wall / Q000201:enzymology; D006026:Glycoside Hydrolases; D008970:Molecular Weight; D009161:Mycobacterium / Q000201:enzymology*; D010430:Pentosyltransferases / Q000302:isolation & purification / Q000378:metabolism; D011108:Polymers; D011134:Polysaccharides / Q000096:biosynthesis* / Q000737:chemistry
D011108:Polymers; D011134:Polysaccharides; C030080:araban; D010430:Pentosyltransferases; C101967:arabinosyltransferase; D006026:Glycoside Hydrolases