Structural identification of metabolites produced by the NodB and NodC proteins of Rhizobium leguminosarum
- 1 September 1994
- journal article
- Published by Wiley in Molecular Microbiology
- Vol. 13 (5), 821-831
- https://doi.org/10.1111/j.1365-2958.1994.tb00474.x
Abstract
The Rhizobium nodulation genes nodABC are involved in the synthesis of lipo‐chitin oligosac‐charides. We have analysed the metabolites which are produced in vivo and in vitro by Rhizobium strains which express the single nodA, nodB and nodC genes or combinations of the three. In vivo radioactive labelling experiments, in which D‐[1‐14C]‐glucosamine was used as a precursor, followed by mass spectrometric analysis of the purified radiolabelled metabolic products, showed that Rhizobium strains that only express the combination of the nodB and nodC genes do not produce lipo‐chitin oligosaccharides but instead produce chitin oligomers (mainly pentamers) which are devoid of the N‐acetyl group on the non‐reducing terminal sugar residue (designated NodBC metabolites). Using the same procedure we have shown that when the nodL gene is expressed in addition to the nodBC genes the majority of metabolites contain an additional O‐acetyl substituent on the non‐reducing terminal sugar residue (designated NodBCL metabolites). The NodBC and NodBCL metabolites purified after in vivo labelling were compared with the radiolabelled metabolites produced in vitro by Rhizobium bacterial cell lysates to which UDP‐N‐acetyl‐D‐[U‐14C]‐glucosamine was added using thin‐layer chromatography. The results show that the lysates of strains which expressed the nodBC or nodBCL genes can also produce NodBC and NodBCL metabolites. The same results were obtained when the NodB and NodC proteins were produced separately in two different strains. On the basis of these and other recent results, we propose that NodB is a chitin oilgosaccharide deacetylase, NodC an N‐acetylglucosaminyltransferase and, by default, NodA is involved in lipie attachment.Keywords
This publication has 32 references indexed in Scilit:
- GENETICS AND MOLECULAR BIOLOGY OF CHITIN SYNTHESIS IN FUNGIAnnual Review of Microbiology, 1993
- Lipo-oligosaccharide nodulation factors: A new class of signaling molecules mediating recognition and morphogenesisCell, 1993
- Research NotesIdentification of the NodC Protein in the Inner but Not the Outer Membrane ofRhizobium leguminosarumMolecular Plant-Microbe Interactions®, 1993
- Rhizobial Lipo-oligosaccharide Signals and Their Role in Plant Morphogenesis; Are Analogous Lipophilic ChitinDerivatives Produced by the Plant?Functional Plant Biology, 1993
- Research NotesHomology ofRhizobium melilotiNodC to Polysaccharide Polymerizing EnzymesMolecular Plant-Microbe Interactions®, 1992
- A novel highly unsaturated fatty acid moiety of lipo-oligosaccharide signals determines host specificity of RhizobiumNature, 1991
- Chitin and nodulationNature, 1991
- Broad host range DNA cloning system for gram-negative bacteria: construction of a gene bank of Rhizobium meliloti.Proceedings of the National Academy of Sciences, 1980
- High frequency transfer of nodulating ability between strains and species of RhizobiumNature, 1978
- A RAPID METHOD OF TOTAL LIPID EXTRACTION AND PURIFICATIONCanadian Journal of Biochemistry and Physiology, 1959