|
|
|
|
|
|
Identification and Biosynthesis of Cyclic Enterobacterial Common Antigen in Escherichia coli. Paul J. A. Erbel, 2003.Phosphoglyceride-linked enterobacterial common antigen (ECAPG) is a cell surface glycolipid that is synthesized by all gram-negative enteric bacteria . The carbohydrate portion of ECAPG consists of linear heteropolysaccharide chains comprised of the trisaccharide repeat unit Fuc4NAc-ManNAcA-GlcNAc, where Fuc4NAc is 4-acetamido-4,6-dideoxy-D-galactose, ManNAcA is N-acetyl-D-mannosaminuronic acid, and GlcNAc is N-acetyl-D-glucosamine . The potential reducing terminal GlcNAc residue of each polysaccharide chain is linked via phosphodiester linkage to a phosphoglyceride aglycone . We demonstrate here the occurrence of a water-soluble cyclic form of enterobacterial common antigen, ECACYC, purified from Escherichia coli strains B and K-12 with solution nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and additional biochemical methods . The ECACYC molecules lacked an aglycone and contained four trisaccharide repeat units that were nonstoichiometrically substituted with up to four O-acetyl groups . ECACYC was not detected in mutant strains that possessed null mutations in the wecA, wecF, and wecG genes of the wec gene cluster . These observations corroborate the structural data obtained by NMR and ESI-MS analyses and show for the first time that the trisaccharide repeat units of ECACYC and ECAPG are assembled by a common biosynthetic pathway .
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
