Structural element responsible for the Fe(III)-phytosiderophore specific transport by HvYS1 transporter in barley.
Hordeum vulgare L. yellow stripe 1 (HvYS1) is a selective transporter for Fe(III)-phytosiderophores, involved in primary iron acquisition from soils in barley roots. In contrast, Zea mays yellow stripe 1 (ZmYS1) in maize possesses broad substrate specificity, despite a high homology with HvYS1. Here we revealed, by assessing the transport activity of a series of HvYS1-ZmYS1 chimeras, that the outer membrane loop between the sixth and seventh transmembrane regions is essential for substrate specificity. Circular dichroism spectra indicated that a synthetic peptide corresponding to the loop of HvYS1 forms an alpha-helix in solution, whereas that of ZmYS1 is flexible. We propose that the structural difference at this particular loop determines the substrate specificity of the HvYS1 transporter.
Harada
Emiko
E
Suntory Institute for Bioorganic Research, 1-1-1 Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka 618-8503, Japan.
Sugase
Kenji
K
Namba
Kosuke
K
Iwashita
Takashi
T
Murata
Yoshiko
Y
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D001467:Hordeum / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000737:chemistry / Q000494:pharmacology; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000378:metabolism; D017262:Siderophores / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity / Q000187:drug effects; D014981:Xenopus; D003313:Zea mays / Q000378:metabolism*
D007502:Iron Chelating Agents; D010940:Plant Proteins; D011994:Recombinant Proteins; D017262:Siderophores; D007501:Iron