Open AccessThree Genes Encoding for Putative Methyl- and Acetyltransferases Map Adjacent to the wzm and wzt Genes and Are Essential for O-Antigen Biosynthesis in Rhizobium etli CE3
Author(s) -
Inge Lerouge,
Christel Verreth,
Jan Michiels,
Russell W. Carlson,
Anup Datta,
Mengsheng Gao,
Jozef Vanderleyden
Publication year - 2003
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi.2003.16.12.1085
Subject(s) - orfs , gene , methyltransferase , biology , acetyltransferases , open reading frame , genetics , mutant , transferase , biochemistry , peptide sequence , enzyme , methylation , acetylation
The elucidation of the structure of the O-antigen of Rhizo-bium etli CE3 predicts that the R. etli CE3 genome must contain genes encoding acetyl- and methyltransferases to confer the corresponding modifications to the O-antigen. We identified three open reading frames (ORFs) upstream of wzm, encoding the membrane component of the O-antigen transporter and located in the lpsα-region of R. etli CE3. The ORFs encode two putative acetyltransferases with similarity to the CysE-LacA-LpxA-NodL family of acetyl-transferases and one putative methyltransferase with sequence motifs common to a wide range of S-adenosyl-L-methionine-dependent methyltransferases. Mutational analysis of the ORFs encoding the putative acetyltrans-ferases and methyltransferase revealed that the acetyl and methyl decorations mediated by these specific enzymes are essential for O-antigen synthesis. Composition analysis and high performance anion exchange chromatography analysis of the lipopolysaccharides (LPSs) of the mutants show that all of these LPSs contain an intact core region and lack the O-antigen polysaccharide. The possible role of these transferases in the decoration of the O-antigen of R. etli is discussed.