7VSQ

Crystal strcuture of the tandem B-Box domains of CONSTANS

Summary for 7VSQ

• Entry DOI: 10.2210/pdb7vsq/pdb
• Descriptor: Zinc finger protein CONSTANS, ZINC ION (3 entities in total)
• Functional Keywords: b-box, constans, photoperiod, plant protein
• Biological source: Arabidopsis thaliana (Mouse-ear cress)
• Total number of polymer chains: 3
• Total formula weight: 33864.03

Authors

Liu, R.,Lv, X.,Du, J. (deposition date: 2021-10-27, release date: 2022-03-02, Last modification date: 2023-11-29)

Primary citation

Zeng, X.,Lv, X.,Liu, R.,He, H.,Liang, S.,Chen, L.,Zhang, F.,Chen, L.,He, Y.,Du, J.
Molecular basis of CONSTANS oligomerization in FLOWERING LOCUS T activation.
J Integr Plant Biol, 64:731-740, 2022

PubMed Abstract: The transcription factor CONSTANS (CO) integrates day-length information to induce the expression of florigen FLOWERING LOCUS T (FT) in Arabidopsis. We recently reported that the C-terminal CCT domain of CO forms a complex with NUCLEAR FACTOR-YB/YC to recognize multiple cis-elements in the FT promoter, and the N-terminal tandem B-box domains form a homomultimeric assembly. However, the mechanism and biological function of CO multimerization remained unclear. Here, we report that CO takes on a head-to-tail oligomeric configuration via its B-boxes to mediate FT activation in long days. The crystal structure of B-boxes reveals a closely connected tandem B-box fold forming a continuous head-to-tail assembly through unique CDHH zinc fingers. Mutating the key residues involved in CO oligomerization resulted in a non-functional CO, as evidenced by the inability to rescue co mutants. By contrast, a transgene encoding a human p53-derived tetrameric peptide in place of the B-boxes rescued co mutant, emphasizing the essential role of B-boxes -mediated oligomerization. Furthermore, we found that the four TGTG-bearing cis-elements in FT proximal promoter are required for FT activation in long days. Our results suggest that CO forms a multimer to bind to the four TGTG motifs in the FT promoter to mediate FT activation.

PubMed: 35023269
DOI: 10.1111/jipb.13223

Experimental method

X-RAY DIFFRACTION (2.7 Å)