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The nodC protein of Azorhizobium caulinodans is an N-acetylglucosaminyltransferase
- Geremia, R.A., Mergaert, P., Geelen, D., Montagu, M. van., Holsters, M.
- Proceedings of the National Academy of Sciences of the United States of America 1994 v.91 no.7 pp. 2669-2673
- Rhizobiaceae, hexosyltransferases, enzyme activity, nodulation, structural genes, oligosaccharides
- Nod factors are signal molecules produced by Azorhizobium, Bradyrhizobium, and Rhizobium species that trigger nodule formation in leguminous host plants. The backbone of Nod factors consists of a beta-1,4-N-acetylglucosamine oligosaccharide from which the N-acetyl group at the nonreducing end is replaced by a fatty acid. The nodABC gene products are necessary for backbone biosynthesis. By incubation of cell extracts from Azorhizobium caulinodans with radioactive uridine diphosphate-N-acetylglucosamine, Nod factor precursors were identified and characterized as beta-1,4-N-acetylglucosamine oligosaccharides. By analysis of different nod gene mutants and by expression of nodC in Escherichia coli, the N-acetylglucosaminyltransferase activity was ascribed to the NodC protein. The results suggest that the first step in biosynthesis of Nod factors is the assembly of the oligosaccharide chain.