J. Bacteriol. doi:10.1128/JB.00910-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
The amino terminus of Bacillus subtilis TagB possesses separable localization and functional properties
Amit P. Bhavsar,
Michael A. D'Elia,
Tiffany D. Sahakian,
and
Eric D. Brown*
From the Antimicrobial Research Centre and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
* To whom correspondence should be addressed. Email:
ebrown{at}mcmaster.ca.
 |
Abstract |
|---|
The function(s) of Gram-positive wall teichoic acid is emerging with recent findings that it is an important virulence factor in the pathogen Staphylococcus aureus and that it is crucial to proper rod-shaped cell morphology of Bacillus subtilis. Despite its importance, our understanding of teichoic acid biosynthesis remains incomplete. The TagB protein has been implicated in the priming step of poly(glycerol phosphate) wall teichoic acid synthesis in B. subtilis. Work to date indicates that the TagB protein is localized to the membrane where it adds a single glycerol phosphate residue to the non-reducing end of the undecaprenol-phosphate-linked N-acetylmannosamine-
(1,4)-N-acetylglucosamine-1-phosphate. Thus membrane association is critical to TagB function. In this work we elucidate the mechanism of TagB membrane localization. We report the identification of a membrane targeting determinant at the amino terminus of TagB that is necessary and sufficient for membrane localization. The putative amphipathicity of this membrane targeting determinant was characterized and shown to be required for TagB function, but not localization. This work shows for the first time that the amino terminus of TagB mediates membrane targeting and protein function.