8XAT

Crystal structure of AtARR1(RD-DBD)

8XAT の概要

• エントリーDOI: 10.2210/pdb8xat/pdb
• 分子名称: Two-component response regulator ARR1 (2 entities in total)
• 機能のキーワード: cytokinin, phosphorelay, b-arr, dna binding protein
• 由来する生物種: Arabidopsis thaliana (thale cress)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 66537.30

構造登録者

Li, J.X.,Zhou, C.M.,Zhang, P.,Wang, J.W. (登録日: 2023-12-05, 公開日: 2024-01-24)

主引用文献

Zhou, C.M.,Li, J.X.,Zhang, T.Q.,Xu, Z.G.,Ma, M.L.,Zhang, P.,Wang, J.W.
The structure of B-ARR reveals the molecular basis of transcriptional activation by cytokinin.
Proc.Natl.Acad.Sci.USA, 121:e2319335121-e2319335121, 2024

PubMed Abstract: The phytohormone cytokinin has various roles in plant development, including meristem maintenance, vascular differentiation, leaf senescence, and regeneration. Prior investigations have revealed that cytokinin acts via a phosphorelay similar to the two-component system by which bacteria sense and respond to external stimuli. The eventual targets of this phosphorelay are type-B ARABIDOPSIS RESPONSE REGULATORS (B-ARRs), containing the conserved N-terminal receiver domain (RD), middle DNA binding domain (DBD), and C-terminal transactivation domain. While it has been established for two decades that the phosphoryl transfer from a specific histidyl residue in ARABIDOPSIS HIS PHOSPHOTRANSFER PROTEINS (AHPs) to an aspartyl residue in the RD of B-ARRs results in a rapid transcriptional response to cytokinin, the underlying molecular basis remains unclear. In this work, we determine the crystal structures of the RD-DBD of ARR1 (ARR1) as well as the ARR1-DNA complex from . Analyses of the ARR1-DNA complex have revealed the structural basis for sequence-specific recognition of the GAT trinucleotide by ARR1. In particular, comparing the ARR1 and ARR1-DNA structures reveals that unphosphorylated ARR1 exists in a closed conformation with extensive contacts between the RD and DBD. In vitro and vivo functional assays have further suggested that phosphorylation of the RD weakens its interaction with DBD, subsequently permits the DNA binding capacity of DBD, and promotes the transcriptional activity of ARR1. Our findings thus provide mechanistic insights into phosphorelay activation of gene transcription in response to cytokinin.

PubMed: 38198526
DOI: 10.1073/pnas.2319335121

実験手法

X-RAY DIFFRACTION (2.205 Å)