7NB0 image
Entry Detail
PDB ID:
7NB0
Keywords:
Title:
Structure of the DNA-binding domain of SEPALLATA 3
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2021-01-25
Release Date:
2021-07-14
Method Details:
Experimental Method:
Resolution:
2.10 Å
R-Value Free:
0.23
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Developmental protein SEPALLATA 3
Chain IDs:A, B, C, D
Chain Length:57
Number of Molecules:4
Biological Source:Arabidopsis thaliana
Primary Citation
The intervening domain is required for DNA-binding and functional identity of plant MADS transcription factors.
Nat Commun 12 4760 4760 (2021)
PMID: 34362909 DOI: 10.1038/s41467-021-24978-w

Abstact

The MADS transcription factors (TF) are an ancient eukaryotic protein family. In plants, the family is divided into two main lineages. Here, we demonstrate that DNA binding in both lineages absolutely requires a short amino acid sequence C-terminal to the MADS domain (M domain) called the Intervening domain (I domain) that was previously defined only in type II lineage MADS. Structural elucidation of the MI domains from the floral regulator, SEPALLATA3 (SEP3), shows a conserved fold with the I domain acting to stabilise the M domain. Using the floral organ identity MADS TFs, SEP3, APETALA1 (AP1) and AGAMOUS (AG), domain swapping demonstrate that the I domain alters genome-wide DNA-binding specificity and dimerisation specificity. Introducing AG carrying the I domain of AP1 in the Arabidopsis ap1 mutant resulted in strong complementation and restoration of first and second whorl organs. Taken together, these data demonstrate that the I domain acts as an integral part of the DNA-binding domain and significantly contributes to the functional identity of the MADS TF.

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