This Article Full Text Full Text (PDF) Other Versions of this Article: JB.01423-07v1 190/2/571    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hacker, S. Articles by Narberhaus, F. Search for Related Content PubMed PubMed Citation Articles by Hacker, S. Articles by Narberhaus, F.

 Previous Article  |  Next Article 

Journal of Bacteriology, January 2008, p. 571-580, Vol. 190, No. 2
0021-9193/08/$08.00+0     doi:10.1128/JB.01423-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Multiple Phospholipid N-Methyltransferases with Distinct Substrate Specificities Are Encoded in Bradyrhizobium japonicum

Stephanie Hacker,^1, Christian Sohlenkamp,^2, Meriyem Aktas,¹ Otto Geiger,² and Franz Narberhaus^1*

Lehrstuhl für Biologie der Mikroorganismen, Ruhr-Universität Bochum, Bochum, Germany,¹ Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México²

Received 3 September 2007/ Accepted 26 October 2007

Phosphatidylcholine (PC) is the major phospholipid in eukaryotic membranes. In contrast, it is found in only a few prokaryotes including members of the family Rhizobiaceae. In these bacteria, PC is required for pathogenic and symbiotic plant-microbe interactions, as shown for Agrobacterium tumefaciens and Bradyrhizobium japonicum. At least two different phospholipid N-methyltransferases (PmtA and PmtX) have been postulated to convert phosphatidylethanolamine (PE) to PC in B. japonicum by three consecutive methylation reactions. However, apart from the known PmtA enzyme, we identified and characterized three additional pmt genes (pmtX1, pmtX3, and pmtX4), which can be functionally expressed in Escherichia coli, showing different substrate specificities. B. japonicum expressed only two of these pmt genes (pmtA and pmtX1) under all conditions tested. PmtA predominantly converts PE to monomethyl PE, whereas PmtX1 carries out both subsequent methylation steps. B. japonicum is the first bacterium known to use two functionally different Pmts. It also expresses a PC synthase, which produces PC via condensation of CDP-diacylglycerol and choline. Our study shows that PC biosynthesis in bacteria can be much more complex than previously anticipated.

Published ahead of print on 9 November 2007.

S.H. and C.S. contributed equally to this study.