The Amino Terminus of Bacillus subtilis TagB Possesses Separable Localization and Functional Properties

Antimicrobial Research Centre, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada.
Journal of Bacteriology (Impact Factor: 2.81). 11/2007; 189(19):6816-23. DOI: 10.1128/JB.00910-07
Source: PubMed


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 nonreducing end of the undecaprenol-phosphate-linked N-acetylmannosamine-β(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.

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Available from: Amit P Bhavsar
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    • "As described in the introduction, WTA precursors are synthesized in the cytoplasm on an undecaprenyl phosphate carrier lipid embedded in the membrane (Swoboda et al., 2009a). The first enzyme in the WTA biosynthetic pathway, TagO, is an integral membrane protein, but many of the other enzymes involved in assembly of the WTA polymer do not have predicted membrane-spanning regions, although it is presumed that they are membraneassociated either directly or indirectly (Bhavsar et al., 2007; Formstone et al., 2008). "
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