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The nodulation gene nolK of Azorhizobium caulinodans is involved in the formation of GDP‐fucose from GDP‐mannose
Author(s) -
Mergaert Peter,
Van Montagu Marc,
Holsters Marcelle
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00461-4
Subject(s) - fucose , biochemistry , fucosylation , mannose , biology , chemistry , escherichia coli , nad+ kinase , enzyme , gene , glycoprotein
The nolK gene of Azorhizobium caulinodans is essential for the incorporation of a fucosyl group in Nod factors. A NAD(P)‐binding site is present in the NolK amino acid sequence and the gene is homologous to Escherichia coli genes, presumably involved in GDP‐fucose synthesis. Protein extracts of A. caulinodans , overexpressing nolK , have an enzyme activity that synthesizes GDP‐fucose from GDP‐mannose. nolK most probably encodes a 4‐reductase performing the last step in GDP‐fucose synthesis. Wild‐type A. caulinodans produces a population of fucosylated and non‐fucosylated molecules but the nolK ‐overexpressing strain produces only fucosylated Nod factors. Thus, the production of activated fucosyl donors is a rate‐limiting step in Nod factor fucosylation.