Journal
PLOS ONE
Volume 10, Issue 11, Pages -Publisher
PUBLIC LIBRARY SCIENCE
DOI: 10.1371/journal.pone.0142870
Keywords
-
Categories
Funding
- Agence Nationale de la Recherche (Bactoprenyl project) [ANR-11-BSV3-002]
- Belgian State-Federal Science Policy (InterUniversity Attraction Poles Program, iProS project) [P7/44]
- Centre National de la Recherche Scientifique
- University of Paris Sud
Ask authors/readers for more resources
Several integral membrane proteins exhibiting undecaprenyl-pyrophosphate (C-55-PP) phosphatase activity were previously identified in Escherichia coli that belonged to two distinct protein families: the BacA protein, which accounts for 75% of the C-55-PP phosphatase activity detected in E. coli cell membranes, and three members of the PAP2 phosphatidic acid phosphatase family, namely PgpB, YbjG and LpxT. This dephosphorylation step is required to provide the C-55-P carrier lipid which plays a central role in the biosynthesis of various cell wall polymers. We here report detailed investigations of the biochemical properties and membrane topology of the BacA protein. Optimal activity conditions were determined and a narrow-range substrate specificity with a clear preference for C-55-PP was observed for this enzyme. Alignments of BacA protein sequences revealed two particularly well-conserved regions and several invariant residues whose role in enzyme activity was questioned by using a site-directed mutagenesis approach and complementary in vitro and in vivo activity assays. Three essential residues Glu21, Ser27, and Arg174 were identified, allowing us to propose a catalytic mechanism for this enzyme. The membrane topology of the BacA protein determined here experimentally did not validate previous program-based predicted models. It comprises seven transmembrane segments and contains in particular two large periplasmic loops carrying the highly-conserved active site residues. Our data thus provide evidence that all the different E. coli C-55-PP phosphatases identified to date (BacA and PAP2) catalyze the dephosphorylation of C-55-PP molecules on the same (outer) side of the plasma membrane.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available