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真菌和植物乙酰羟酸合酶结构获解析
2020-07-10 13:48

近日,澳大利亚昆士兰大学Luke W. Guddat、Thierry Lonhienne等研究人员合作解析出真菌和植物乙酰羟酸合酶(AHAS)的结构。2020年7月8日,《自然》杂志在线发表了这项成果。

研究人员报道了酿酒酵母中十六聚体的以及拟南芥中十二聚体的AHAS复合物结构。研究结果表明,调节亚基形成核心,而催化亚基二聚体附着在其上,呈“马耳他十字”的形状。
 
该结构显示催化亚基和调节亚基如何相互连通,从而为支链氨基酸(BCAA)的激活和抑制反馈提供了途径。研究人员还发现,结核分枝杆菌AHAS采用相似的结构,由此表明整个AHAS体系结构在各界之间都是保守的。
 
据悉,乙酰羟酸合酶(AHAS),也称为乙酰乳酸合酶,是一种FAD和ThDP-Mg2+依赖型酶,可催化BCAA生物合成的第一步。它是50多种商业除草剂的靶标。AHAS需要催化亚基和调节亚基才能发挥最大活性和功能。
 
附:英文原文

Title: Structures of fungal and plant acetohydroxyacid synthases

Author: Thierry Lonhienne, Yu Shang Low, Mario D. Garcia, Tristan Croll, Yan Gao, Quan Wang, Lou Brillault, Craig M. Williams, James A. Fraser, Ross P. McGeary, Nicholas P. West, Michael J. Landsberg, Zihe Rao, Gerhard Schenk, Luke W. Guddat

Issue&Volume: 2020-07-08

Abstract: Acetohydroxyacid synthase (AHAS), also known as acetolactate synthase, is a FAD and ThDP-Mg2+-dependent enzyme that catalyses the first step in the biosynthesis of the branched chain amino acids (BCAAs)1. It is the target for over 50 commercial herbicides2. AHAS requires both catalytic and regulatory subunits for maximal activity and functionality. Herein, our structures of the hexadecameric Saccharomyces cerevisiae and dodecameric Arabidopsis thaliana AHAS complexes demonstrate that the regulatory subunits form a core upon which the catalytic subunit dimers are attached, adopting the shape of a “Maltese Cross”. The structures show how the catalytic and regulatory subunits communicate with each other to provide a pathway for activation and for feedback inhibition by the BCAAs. We also show that Mycobacterium tuberculosis AHAS adopts a similar structure, thus demonstrating that the overall AHAS architecture is conserved across kingdoms.

DOI: 10.1038/s41586-020-2514-3

Source: https://www.nature.com/articles/s41586-020-2514-3

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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