Biosynthesis of Rhizobium meliloti lipooligosaccharide Nod factors: NodA is required for an N-acyltransferase activity

Journal Article · Tue Aug 30 00:00:00 EDT 1994 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.91.18.8418· OSTI ID:6722884

Atkinson, E M; Long, S R ^[1]; Palcic, M M; Hindsgaul, O ^[2]

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1. Stanford Univ., CA (United States)
2. Univ. of Alberta, Edmonton (Canada)

Rhizobium bacteria synthesize N-acylated [beta]-1,4-N-acetylglucosamine lipooligosaccharides, called Nod factors, which act as morphogenic signal molecules to legume roots during development of nitrogen-fixing nodules. The biosynthesis of Nod factors is genetically dependent upon the nodulation (nod) genes, including the common nod genes nodABC. We used the Rhizobium meliloti NodH sulfotransferase to prepare [sup 35]S-labeled oligosaccharides which served as metabolic tracers for Nod enzyme activities. This approach provides a general method for following chitooligosaccharide modifications. We found nodAB-dependent conversion of N-acetylchitotetraose (chitotetraose) monosulfate into hydrophobic compounds which by chromatographic and chemical tests were equivalent to acylated Nod factors. Sequential incubation of labeled intermediates with Escherichia coli containing either NodA or NodB showed that NodB was required before NodA during Nod factor biosynthesis. The acylation activity was sensitive to oligosaccharide chain length, with chitotetraose serving as a better substrate than chitobiose or chitotriose. We constructed a putative Nod factor intermediate, GlcN-[beta]1,4-(GlcNac)[sub 3], by enzymatic synthesis and labeled it by NodH-mediated sulfation to create a specific metabolic probe. Acylation of this oligosaccharide required only NodA. These results confirm previous reports that NodB is an N-deacetylase and suggest that NodA is an N-acyltransferase. 31 refs., 6 figs.

• DOE Contract Number: FG03-90ER20010
• OSTI ID: 6722884
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 91:18; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
OLIGOSACCHARIDES
BIOSYNTHESIS
GENETIC CONTROL
RHIZOBIUM
BIOCHEMISTRY
GENES
NITROGEN TRANSFERASES
BACTERIA
CARBOHYDRATES
CHEMISTRY
CONTROL
ENZYMES
MICROORGANISMS
ORGANIC COMPOUNDS
PEST CONTROL
PROTEINS
SACCHARIDES
SYNTHESIS
TRANSFERASES
550700* - Microbiology
550200 - Biochemistry