| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, PO Box 174 Correo 22, Santiago, Chile
2 Infectious Diseases Research Group, Siebens–Drake Research Institute, Department of Microbiology and Immunology, University of Western Ontario, London, ON N6A 5C1, Canada
3 Infectious Diseases Research Group, Siebens–Drake Research Institute, Department of Medicine, University of Western Ontario, London, ON N6A 5C1, Canada
Correspondence
Miguel A. Valvano
mvalvano{at}uwo.ca
Inés Contreras
icontrer{at}uchile.cl
WbaP is a membrane enzyme that initiates O antigen synthesis in Salmonella enterica by catalysing the transfer of galactose 1-phosphate (Gal-1-P) onto undecaprenyl phosphate (Und-P). WbaP possesses at least three predicted structural domains: an N-terminal region containing four transmembrane helices, a large central periplasmic loop, and a C-terminal domain containing the last transmembrane helix and a large cytoplasmic tail. In this work, we investigated the contribution of each region to WbaP function by constructing a series of mutant WbaP proteins and using them to complement O antigen synthesis in 
wbaP mutants of S. enterica serovars Typhi and Typhimurium. Truncated forms of WbaP lacking the periplasmic loop exhibited altered chain-length distributions in O antigen polymerization, suggesting that this central domain is involved in modulating the chain-length distribution of the O polysaccharide. The N-terminal and periplasmic domains were dispensable for complementation of O antigen synthesis in vivo, suggesting that the C-terminal domain carries the sugar-phosphate transferase activity. However, despite the fact that they complemented the synthesis of O antigen in the wbaP mutant in vivo, membrane extracts containing WbaP derivatives without the N-terminal domain failed to transfer radioactive Gal from UDP-Gal into a lipid-rich fraction. These results suggest that the N-terminal region of WbaP, which contains four transmembrane domains, is essential for the insertion or stability of the protein in the bacterial membrane. We propose that the domain structure of WbaP enables this protein not only to function in the transfer of Gal-1-P to Und-P but also to establish critical interactions with additional proteins required for the correct assembly of O antigen in S. enterica.
These authors contributed equally to this work.
Present address: Departamento de Ciencias Biológicas, Facultad de Ciencias de la Salud, Universidad Nacional Andrés Bello, Santiago, Chile.
This article has been cited by other articles:
|
|
 |
|
  K. Ilg, K. Endt, B. Misselwitz, B. Stecher, M. Aebi, and W.-D. Hardt O-Antigen-Negative Salmonella enterica Serovar Typhimurium Is Attenuated in Intestinal Colonization but Elicits Colitis in Streptomycin-Treated Mice Infect. Immun., June 1, 2009; 77(6): 2568 - 2575. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Zarschler, B. Janesch, S. Zayni, C. Schaffer, and P. Messner Construction of a Gene Knockout System for Application in Paenibacillus alvei CCM 2051T, Exemplified by the S-Layer Glycan Biosynthesis Initiation Enzyme WsfP Appl. Envir. Microbiol., May 15, 2009; 75(10): 3077 - 3085. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Larue, M. S. Kimber, R. Ford, and C. Whitfield Biochemical and Structural Analysis of Bacterial O-antigen Chain Length Regulator Proteins Reveals a Conserved Quaternary Structure J. Biol. Chem., March 13, 2009; 284(11): 7395 - 7403. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Cuthbertson, I. L. Mainprize, J. H. Naismith, and C. Whitfield Pivotal Roles of the Outer Membrane Polysaccharide Export and Polysaccharide Copolymerase Protein Families in Export of Extracellular Polysaccharides in Gram-Negative Bacteria Microbiol. Mol. Biol. Rev., March 1, 2009; 73(1): 155 - 177. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Jimenez, R. Canals, M. T. Salo, S. Vilches, S. Merino, and J. M. Tomas The Aeromonas hydrophila wb*O34 Gene Cluster: Genetics and Temperature Regulation J. Bacteriol., June 15, 2008; 190(12): 4198 - 4209. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. L. Marolda, E. R. Haggerty, M. Lung, and M. A. Valvano Functional Analysis of Predicted Coiled-Coil Regions in the Escherichia coli K-12 O-Antigen Polysaccharide Chain Length Determinant Wzz J. Bacteriol., March 15, 2008; 190(6): 2128 - 2137. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
