2MUK

1H, 13C, and 15N Chemical Shift Assignments for AUX/IAA17

DOI: 10.2210/pdb2MUK/pdb
BMRB: 25217

Classification: TRANSCRIPTION
Organism(s): Arabidopsis thaliana
Expression System: Escherichia coli
Mutation(s): No

Deposited: 2014-09-11 Released: 2014-12-17
Deposition Author(s): Suh, J., Han, M.

Experimental Data Snapshot

Method: SOLUTION NMR
Conformers Calculated: 100
Conformers Submitted: 20
Selection Criteria: structures with the least restraint violations

wwPDB Validation 3D Report Full Report

This is version 1.1 of the entry. See complete history.

Literature

Structural basis for the auxin-induced transcriptional regulation by Aux/IAA17.

Han, M., Park, Y., Kim, I., Kim, E.H., Yu, T.K., Rhee, S., Suh, J.Y.

(2014) Proc Natl Acad Sci U S A 111: 18613-18618

PubMed: 25512488 Search on PubMedSearch on PubMed Central
DOI: 10.1073/pnas.1419525112
Primary Citation of Related Structures:
2MUK

PubMed Abstract:

Auxin is the central hormone that regulates plant growth and organ development. Transcriptional regulation by auxin is mediated by the auxin response factor (ARF) and the repressor, AUX/IAA. Aux/IAA associates with ARF via domain III-IV for transcriptional repression that is reversed by auxin-induced Aux/IAA degradation. It has been known that Aux/IAA and ARF form homo- and hetero-oligomers for the transcriptional regulation, but what determines their association states is poorly understood. Here we report, to our knowledge, the first solution structure of domain III-IV of Aux/IAA17 (IAA17), and characterize molecular interactions underlying the homotypic and heterotypic oligomerization. The structure exhibits a compact β-grasp fold with a highly dynamic insert helix that is unique in Aux/IAA family proteins. IAA17 associates to form a heterogeneous ensemble of front-to-back oligomers in a concentration-dependent manner. IAA17 and ARF5 associate to form homo- or hetero-oligomers using a common scaffold and binding interfaces, but their affinities vary significantly. The equilibrium dissociation constants (KD) for homo-oligomerization are 6.6 μM and 0.87 μM for IAA17 and ARF5, respectively, whereas hetero-oligomerization reveals a ∼ 10- to ∼ 100-fold greater affinity (KD = 73 nM). Thus, individual homo-oligomers of IAA17 and ARF5 spontaneously exchange their subunits to form alternating hetero-oligomers for transcriptional repression. Oligomerization is mainly driven by electrostatic interactions, so that charge complementarity at the interface determines the binding affinity. Variable binding affinity by surface charge modulation may effectively regulate the complex interaction network between Aux/IAA and ARF family proteins required for the transcriptional control of auxin-response genes.

Organizational Affiliation:

Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul 151-921, Republic of Korea; and jysuh@snu.ac.kr srheesnu@snu.ac.kr.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Auxin-responsive protein IAA17	X	113	Arabidopsis thaliana	Mutation(s): 0 Gene Names: IAA17, AXR3, At1g04250, F19P19.31
Find proteins for P93830 (Arabidopsis thaliana) Explore P93830 Go to UniProtKB: P93830
Protein Feature View Expand
Reference Sequence