title: A surface-associated retinol- and fatty acid-binding protein (Gp-FAR-1) from the potato cyst nematode Globodera pallida: lipid binding activities, structural analysis and expression pattern.
abstract: Parasitic nematodes produce at least two structurally novel classes of small helix-rich retinol- and fatty-acid-binding proteins that have no counterparts in their plant or animal hosts and thus represent potential targets for new nematicides. Here we describe a protein (Gp-FAR-1) from the plant-parasitic nematode Globodera pallida, which is a member of the nematode-specific fatty-acid- and retinol-binding (FAR) family of proteins but localizes to the surface of this species, placing it in a strategic position for interaction with the host. Recombinant Gp-FAR-1 was found to bind retinol, cis-parinaric acid and the fluorophore-tagged lipids 11-(dansylamino)undecanoic acid and dansyl-D,L-alpha-amino-octanoic acid. The fluorescence emission characteristics of the dansylated analogues indicated that the entire ligand enters the binding cavity. Fluorescence competition experiments showed that Gp-FAR-1 binds fatty acids in the range C(11) to C(24), with optimal binding at C(15). Intrinsic fluorescence analysis of a mutant protein into which a tryptophan residue had been inserted supported computer-based predictions of the position of this residue at the protein's interior and possibly also at the binding site. Of direct relevance to plant defence systems was the observation that Gp-FAR-1 binds two lipids (linolenic and linoleic acids) that are precursors of plant defence compounds and the jasmonic acid signalling pathway. Moreover, Gp-FAR-1 was found to inhibit the lipoxygenase-mediated modification of these substrates in vitro. Thus not only does Gp-FAR-1 function as a broad-spectrum retinol- and fatty-acid-binding protein, the results are consistent with the idea that Gp-FAR-1 is involved in the evasion of primary host plant defence systems.
authors.affiliation: Mycology, Bacteriology and Nematology Unit, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK. aprior@scri.sari.ac.uk
authors.forename: A
authors.initials: A
authors.lastname: Prior
authors.forename: J T
authors.initials: JT
authors.lastname: Jones
authors.forename: V C
authors.initials: VC
authors.lastname: Blok
authors.forename: J
authors.initials: J
authors.lastname: Beauchamp
authors.forename: L
authors.initials: L
authors.lastname: McDermott
authors.forename: A
authors.initials: A
authors.lastname: Cooper
authors.forename: M W
authors.initials: MW
authors.lastname: Kennedy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism*; D015870:Gene Expression; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008024:Ligands; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014431:Tylenchoidea / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014801:Vitamin A / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D018076:DNA, Complementary; C430843:FAR-1 protein, Globodera pallida; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D015801:Helminth Proteins; D008024:Ligands; D011994:Recombinant Proteins; D014801:Vitamin A