Open AccessMembrane topology of the Salmonella enterica serovar Typhimurium Group B O‐antigen translocase Wzx
Author(s) -
Cunneen Monica M.,
Reeves Peter R.
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01295.x
Subject(s) - topology (electrical circuits) , transmembrane protein , translocase , membrane topology , salmonella enterica , transmembrane domain , biology , cytoplasm , gene , chemistry , computational biology , genetics , chromosomal translocation , escherichia coli , mathematics , receptor , combinatorics
The O‐antigen translocase, Wzx, is involved in translocation of bacterial polysaccharide repeat units across the cytoplasmic membrane, and is an unusually diverse, highly hydrophobic protein, with high numbers of predicted α‐helical transmembrane segments (TMS). The Salmonella enterica serovar Typhimurium Group B O‐antigen Wzx was an ideal candidate for topological study as the O‐antigen gene cluster is one of only a few that have been well characterized. The topology profile prediction for this protein was determined using five programs, with different recognition parameters, which consistently predict that 12 TMS are present. A membrane topology model was constructed by analysis of lacZ and phoA gene fusions at randomly selected and targeted fusion sites within wzx . Enzyme activity of these, and full‐length C‐terminal fusion proteins, confirmed the 12‐TMS topology for this Wzx, and also indicated that the C‐terminus was located within the cytoplasm, which is consistent with the predicted topology.