Structural insight into brassinosteroid perception by BRI1

Article

关键词: RECEPTOR KINASE BRI1;    SIGNAL-TRANSDUCTION;    TRANSCRIPTION FACTORS;    ARABIDOPSIS-THALIANA;    EXTRACELLULAR DOMAIN;    PLANT-GROWTH;    COMPLEX;    PHOSPHORYLATION;    ACTIVATION;    BRI1/BAK1;   

DOI  :  10.1038/nature10178

来源: SCIE

【 摘 要 】

Brassinosteroids are essential phytohormones that have crucial roles in plant growth and development. Perception of brassinosteroids requires an active complex of BRASSINOSTEROID-INSENSITIVE 1 (BRI1) and BRI1-ASSOCIATED KINASE 1 (BAK1). Recognized by the extracellular leucine-rich repeat (LRR) domain of BRI1, brassinosteroids induce a phosphorylation-mediated cascade to regulate gene expression. Here we present the crystal structures of BRI1(LRR) in free and brassinolide-bound forms. BRI1(LRR) exists as a monomer in crystals and solution independent of brassinolide. It comprises a helical solenoid structure that accommodates a separate insertion domain at its concave surface. Sandwiched between them, brassinolide binds to a hydrophobicity-dominating surface groove on BRI1(LRR). Brassinolide recognition by BRI1(LRR) is through an induced-fit mechanism involving stabilization of two interdomain loops that creates a pronounced non-polar surface groove for the hormone binding. Together, our results define the molecular mechanisms by which BRI1 recognizes brassinosteroids and provide insight into brassinosteroid-induced BRI1 activation.

【 授权许可】

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