植物の結晶構造の二重親和ナイトレートトランスポーター NRT1.1
Ji Sun1, John R Bankston2, Jian Payandeh3
1Department of Pharmacology, Box 357280, University of Washington, Seattle, Washington 98195, USA.
Nature
|February 28, 2014
まとめ
アラビドプシス NRT1.1の窒素トランスポーターはダイマーとして機能し,低親和度状態と高親和度状態を切り替える. Thr101でのリン酸化は,この二分化を制御し,植物成長に不可欠な二重モードの窒素の吸収を可能にします.
科学分野:
- 植物生物学 植物生物学
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
背景:
- 窒素は植物の成長に不可欠ですが,土壌の濃度は大きく異なります.
- アラビドプシス (Arabidopsis) NRT1.1は二重親和性の窒素トランスポーターであるが,そのメカニズムは不明である.
- 翻訳後の改変,特にThr101のリン酸化は,NRT1.1の活性を調節する.
研究 の 目的:
- NRT1.1のダブル・アフィニティ・トランスポートの構造と分子メカニズムを解明する.
- Thr101のリン酸化がトランスポーター活動と親和状態をどのように制御するかを理解するために.
- NRT1.1機能におけるダイメリゼーションの役割を調査する.
主な方法:
- X線結晶学により,非リン酸化NRTの構造を決定する1.1.1.
- 細胞ベースの光共振エネルギー伝送 (FRET) 測定法で,膜内の二分化を研究する.
- サイト・ダイレクト・ミュータゲネシス (Thr101のフォスフォミメティック変異)
- 基板輸送トンネルの分析.
主要な成果:
- 結晶構造は,非リン酸化NRT1.1が内部向きのホモジマーを形成することを明らかにした.
- Thr101のリン酸化部位はダイマー界面の近くにあり,リン酸化とオリゴメール状態を結びつける.
- 機能的なNRT1.1は細胞膜で二酸化する.
- Thr101のフォスフォミメティック突然変異は二分化を妨害し,その結果,高親和のトランスポーターが生じる.
結論:
- NRT1.1は,二重アフィニティの窒素の吸収のために,リン酸化制御型二酸化スイッチを使用しています.
- このメカニズムは,植物が土壌濃度の広い範囲で窒素吸収を適応させることを可能にします.
- NRT1.1に関する構造的洞察は,栄養媒介の調節のための分子基盤を提供します.
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