title: Transmembrane topology of FRO2, a ferric chelate reductase from Arabidopsis thaliana.
abstract: Iron uptake in Arabidopsis thaliana is mediated by ferric chelate reductase FRO2, a transmembrane protein belonging to the flavocytochrome b family. There is no high resolution structural information available for any member of this family. We have determined the transmembrane topology of FRO2 experimentally using the alkaline phosphatase fusion method. The resulting topology is different from that obtained by theoretical predictions and contains 8 transmembrane helices, 4 of which build up the highly conserved core of the protein. This core is present in the entire flavocytochrome b family. The large water soluble domain of FRO2, which contains NADPH, FAD and oxidoreductase sequence motifs, was located on the inside of the membrane.
authors.affiliation: Department of Molecular Biophysics, Center for Chemistry and Chemical Engineering, Box 124, SE-221 00, Lund, Sweden.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Schagerlöf
authors.forename: Greer
authors.initials: G
authors.lastname: Wilson
authors.forename: Hans
authors.initials: H
authors.lastname: Hebert
authors.forename: Salam
authors.initials: S
authors.lastname: Al-Karadaghi
authors.forename: Cecilia
authors.initials: C
authors.lastname: Hägerhäll
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D003573:Cytochrome b Group / Q000737:chemistry; D017931:DNA Primers; D038181:FMN Reductase / Q000737:chemistry* / Q000235:genetics*; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009249:NADP / Q000378:metabolism; D019255:NADPH Oxidases / Q000737:chemistry; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D003573:Cytochrome b Group; D017931:DNA Primers; D005182:Flavin-Adenine Dinucleotide; D009249:NADP; C036888:cytochrome b558; D038181:FMN Reductase; D019255:NADPH Oxidases; C023903:ferric citrate iron reductase; D000469:Alkaline Phosphatase