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研究揭示植物PIN-FORMED生长素转运蛋白的结构和机制
作者:小柯机器人 发布时间:2022/6/30 20:07:19

丹麦奥胡斯大学Bjørn Panyella Pedersen、德国慕尼黑工业大学Ulrich Z. Hammes等研究人员合作揭示植物PIN-FORMED生长素转运蛋白的结构和机制。该研究于2022年6月29日在线发表于国际一流学术期刊《自然》。

研究人员表示,生长素是具有核心作用的激素,控制着植物生长和发育的几乎所有方面。PIN-FORMED(PIN)家族(也被称为生长素外流载体家族)中的蛋白质是这一过程的关键参与者,控制生长素从细胞膜向细胞外空间的输出。由于缺乏结构和生化数据,PIN介导的辅酶转运的分子机制还不清楚。

研究人员提出了生物物理分析和拟南芥PIN8的三个结构:两个朝外的构象,有和没有生长素,以及一个朝内的构象,与除草剂萘基邻氨甲酰苯甲酸结合。该结构形成一个同源二聚体,每个单体分为一个运输和支架结构域,有一个明确的生长素结合位点。在结合位点旁边,一个脯氨酸-脯氨酸交叉点是与运输有关的结构变化的支点,研究人员表明这与质子和离子梯度无关,可能是由生长素的负电荷驱动。

这些结构和生化数据揭示了一种电梯式的运输机制,让人联想到胆汁酸/钠同向转运体、碳酸氢盐/钠同向转运体和钠/质子反向转运体。这些结果为PIN识别和运输提供了一个全面的分子模型,连接并扩展了一个著名的运输概念框架,并解释了极性生长素运输的核心机制,这是植物生理学、生长和发育的一个核心特征。

附:英文原文

Title: Structures and mechanism of the plant PIN-FORMED auxin transporter

Author: Ung, Kien Lam, Winkler, Mikael, Schulz, Lukas, Kolb, Martina, Janacek, Dorina P., Dedic, Emil, Stokes, David L., Hammes, Ulrich Z., Pedersen, Bjrn Panyella

Issue&Volume: 2022-06-29

Abstract: Auxins are hormones that have central roles and control nearly all aspects of growth and development in plants1,2,3. The proteins in the PIN-FORMED (PIN) family (also known as the auxin efflux carrier family) are key participants in this process and control auxin export from the cytosol to the extracellular space4,5,6,7,8,9. Owing to a lack of structural and biochemical data, the molecular mechanism of PIN-mediated auxin transport is not understood. Here we present biophysical analysis together with three structures of Arabidopsis thaliana PIN8: two outward-facing conformations with and without auxin, and one inward-facing conformation bound to the herbicide naphthylphthalamic acid. The structure forms a homodimer, with each monomer divided into a transport and scaffold domain with a clearly defined auxin binding site. Next to the binding site, a proline–proline crossover is a pivot point for structural changes associated with transport, which we show to be independent of proton and ion gradients and probably driven by the negative charge of the auxin. The structures and biochemical data reveal an elevator-type transport mechanism reminiscent of bile acid/sodium symporters, bicarbonate/sodium symporters and sodium/proton antiporters. Our results provide a comprehensive molecular model for auxin recognition and transport by PINs, link and expand on a well-known conceptual framework for transport, and explain a central mechanism of polar auxin transport, a core feature of plant physiology, growth and development.

DOI: 10.1038/s41586-022-04883-y

Source: https://www.nature.com/articles/s41586-022-04883-y

 

期刊信息

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html

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