Rhizobium NodB Protein Involved in Nodulation Signal Synthesis is a Chitooligosaccharide Deacetylase

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 90; no. 2; pp. 625 - 629
• Main Authors: John, Michael, Rohrig, Horst, Schmidt, Jurgen, Wieneke, Ursula, Schell, Jeff
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 15.01.1993; National Acad Sciences; National Academy of Sciences
• Subjects: Acetates; Acetylglucosamine - metabolism; Agronomy. Soil science and plant productions; Amidohydrolases; Antibodies; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Biochemistry; Biological and medical sciences; Carbohydrate Sequence; Cell Communication - genetics; Chitin - metabolism; chitooligosaccharide deacetylase; Economic plant physiology; Enzymes; Escherichia coli - genetics; Esterases - metabolism; Fundamental and applied biological sciences. Psychology; Genes, Bacterial - genetics; Genetics; Molecular Sequence Data; Molecules; NodB protein; nodulation; Oligosaccharides; Oligosaccharides - metabolism; Plants; Protein refolding; Proteins; Recombinant Proteins - biosynthesis; Recombinant Proteins - isolation & purification; Rhizobium meliloti; Sinorhizobium meliloti - enzymology; Sinorhizobium meliloti - genetics; Substrate Specificity; Sugar alcohols; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Tetrasaccharides; Symbiosis; Purification; Symbiotic relation; Rhizobium meliloti; Enzyme; Escherichia coli; Nodulation; Gene overexpression; Enzymatic activity; Nitrogen fixation; Bacteria; Rhizobiaceae; Recombinant protein; Enterobacteriaceae
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.90.2.625

The common nodulation genes nodABC are conserved in all rhizobia and are involved in synthesis of a lipooligosaccharide signal molecule. This bacterial signal consists of a chitooligosaccharide backbone, which carries at the nonreducing end a fatty acyl chain. The modified chitooligosac-charide molecule triggers development of nodules on the roots of the leguminous host plant. To elucidate the specific role of the NodB protein in nodulation factor synthesis, we have purified recombinant NodB and determined its biochemical role by direct assays. Our data show that the NodB protein of Rhizobium meliloti deacetylates the nonreducing N-acetylglu-cosamine residue of chitooligosaccharides. The monosaccharide N-acetylglucosamine is not deacetylated by NodB. In the pathway of Nod factor synthesis, deacetylation at the nonreducing end of the oligosaccharide backbone may be a necessary requirement for attachment of the fatty acyl chain.