The activity of a putative polyisoprenol-linked sugar translocase (Wzx) involved in Escherichia coli O antigen assembly is independent of the chemical structure of the O repeat.
J Biol Chem
; 274(49): 35129-38, 1999 Dec 03.
Article
in En
| MEDLINE
| ID: mdl-10574995
During O antigen lipopolysaccharide (LPS) synthesis in bacteria, transmembrane migration of undecaprenylpyrophosphate (Und-P-P)-bound O antigen subunits occurs before their polymerization and ligation to the rest of the LPS molecule. Despite the general nature of the translocation process, putative O-antigen translocases display a low level of amino acid sequence similarity. In this work, we investigated whether complete O antigen subunits are required for translocation. We demonstrate that a single sugar, GlcNAc, can be incorporated to LPS of Escherichia coli K-12. This incorporation required the functions of two O antigen synthesis genes, wecA (UDP-GlcNAc:Und-P GlcNAc-1-P transferase) and wzx (O-antigen translocase). Complementation experiments with putative O-antigen translocases from E. coli O7 and Salmonella enterica indicated that translocation of O antigen subunits is independent of the chemical structure of the saccharide moiety. Furthermore, complementation with putative translocases involved in synthesis of exopolysaccharides demonstrated that these proteins could not participate in O antigen assembly. Our data indicate that recognition of a complete Und-P-P-bound O antigen subunit is not required for translocation and suggest a model for O antigen synthesis involving recognition of Und-P-P-linked sugars by a putative complex made of Wzx translocase and other proteins involved in the processing of O antigen.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Membrane Transport Proteins
/
Bacterial Proteins
/
Carrier Proteins
/
O Antigens
/
Escherichia coli Proteins
/
Escherichia coli
Language:
En
Journal:
J Biol Chem
Year:
1999
Document type:
Article
Affiliation country:
Argentina
Country of publication:
Estados Unidos