These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Substrate specificity and kinetic studies of nodulation protein NodL of Rhizobium leguminosarum.
    Author: Bloemberg GV, Lagas RM, van Leeuwen S, Van der Marel GA, Van Boom JH, Lugtenberg BJ, Spaink HP.
    Journal: Biochemistry; 1995 Oct 03; 34(39):12712-20. PubMed ID: 7548024.
    Abstract:
    All lipo-chitin oligosaccharides identified from Rhizobium leguminosarum carry an O-acetyl moiety on C6 of the nonreducing terminal N-acetylglucosamine residue. Previously, we have shown that purified NodL protein, using acetyl-CoA as acetyl donor, in vitro acetylates N-acetylglucosamine, chitin oligosaccharides, and lipo-chitin oligosaccharides. In this paper, the enzymatic properties and substrate specificity of NodL protein were analyzed, using a spectrophotometric assay to quantify NodL transacetylating activity. NodL functions optimally under alkaline conditions. Transacetylating activity has a broad temperature optimum between 28 and 42 degrees C. NodL protein is stable for at least 15 min up to 48 degrees C. Glucosamine, chitosan oligosaccharides, terminally de-N-acetylated chitin derivatives, and cellopentaose were identified as acetyl-accepting substrates for NodL protein. Quantitative substrate specificity studies show that chitin derivatives with a free amino group on the nonreducing terminal residue are the preferred substrates of the NodL protein. Our results strongly indicate that the nonreducing terminally de-N-acetylated chitin oligosaccharides produced by the NodC and NodB enzymes are the in vivo acetyl-accepting substrates for NodL protein.
    [Abstract] [Full Text] [Related] [New Search]