title: A new ioxynil-resistant mutant in Synechocystis PCC 6714: hypothesis on the interaction of ioxynil with the D 1 protein.
abstract: A new Synechocystis 6714 mutant, IoxIIA, resistant to the phenol-type herbicide ioxynil was isolated and characterized. The mutation found in the psbA gene (encoding the D 1 photosystem II protein) is at the same codon 266 as for the first ioxynil-resistant mutant IoxIA previously selected [G. Ajlani, I. Meyer, C. Vernotte, and C. Astier, FEBS Lett. 246, 207-210 (1989)]. In IoxIIA, the change of Asn 266 to Asp gives a 3 x resistance, whereas in IoxIA, the change of the same amino acid to Thr gives a 10 x resistance. The effect of these different amino acid substitutions on the ioxynil resistance phenotype has allowed us to construct molecular models and calculate the hydrogen-bonding energies between the hydroxyl group of ioxynil and the respective amino acids at position 266.
authors.affiliation: Dept. de Biologie, CEA/INRA Saclay, Gif sur Yvette, France.
authors.forename: S
authors.initials: S
authors.lastname: Creuzet
authors.forename: G
authors.initials: G
authors.lastname: Ajlani
authors.forename: C
authors.initials: C
authors.lastname: Vernotte
authors.forename: C
authors.initials: C
authors.lastname: Astier
mesh_terms: D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D004351:Drug Resistance / Q000235:genetics; D017343:Genes, Plant; D006540:Herbicides / Q000494:pharmacology*; D007462:Iodobenzenes / Q000494:pharmacology; D045342:Light-Harvesting Protein Complexes; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009570:Nitriles / Q000494:pharmacology*; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D006540:Herbicides; D007462:Iodobenzenes; D045342:Light-Harvesting Protein Complexes; D009570:Nitriles; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll; C008161:ioxynil