title: The helical propensity of the extracellular loop is responsible for the substrate specificity of Fe(III)-phytosiderophore transporters.
abstract: Hordeum vulgare L. yellow stripe 1 (HvYS1) is a selective transporter of Fe(III)-phytosiderophores in barley that is responsible for iron acquisition from the soil. In contrast, maize Zea mays, yellow stripe 1 (ZmYS1) possesses broad substrate specificity. In this study, a quantitative evaluation of the transport activities of HvYS1 and ZmYS1 chimera proteins revealed that the seventh extracellular membrane loop is essential for substrate specificity. The loop peptides of both transporters were prepared and analysed by circular dichroism and NMR. The spectra revealed a higher propensity for α-helical conformation of the HvYS1 loop peptide and a largely disordered structure for that of ZmYS1. These structural differences are potentially responsible for the substrate specificities of the transporters.
authors.affiliation: Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan.
authors.forename: Erisa
authors.initials: E
authors.lastname: Harada
authors.affiliation: Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugase
authors.affiliation: Department of Pharmaceutical Science, Tokushima University, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Namba
authors.affiliation: Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D018506:Gene Expression Regulation, Plant; D001467:Hordeum / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D017262:Siderophores / Q000737:chemistry / Q000378:metabolism*; D013045:Species Specificity; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014982:Xenopus laevis; D003313:Zea mays / Q000235:genetics / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D017262:Siderophores; C419784:yellow stripe1 protein, Zea mays; D007501:Iron
keywords: YS1 transporter; phytosiderophore; α-helical content