脱落酸
突变体
二聚体
磷酸酶
拟南芥
生物
生物化学
化学
立体化学
磷酸化
基因
有机化学
作者
Noriyuki Nishimura,Katsundo Hitomi,A.S. Arvai,Robert P. Rambo,Chiharu Hitomi,Sean R. Cutler,Julian I. Schroeder,Elizabeth D. Getzoff
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:2009-12-04
卷期号:326 (5958): 1373-1379
被引量:435
标识
DOI:10.1126/science.1181829
摘要
The phytohormone abscisic acid (ABA) acts in seed dormancy, plant development, drought tolerance, and adaptive responses to environmental stresses. Structural mechanisms mediating ABA receptor recognition and signaling remain unknown but are essential for understanding and manipulating abiotic stress resistance. Here, we report structures of pyrabactin resistance 1 (PYR1), a prototypical PYR/PYR1-like (PYL)/regulatory component of ABA receptor (RCAR) protein that functions in early ABA signaling. The crystallographic structure reveals an alpha/beta helix-grip fold and homodimeric assembly, verified in vivo by coimmunoprecipitation. ABA binding within a large internal cavity switches structural motifs distinguishing ABA-free "open-lid" from ABA-bound "closed-lid" conformations. Small-angle x-ray scattering suggests that ABA signals by converting PYR1 to a more compact, symmetric closed-lid dimer. Site-directed PYR1 mutants designed to disrupt hormone binding lose ABA-triggered interactions with type 2C protein phosphatase partners in planta.
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