6L5K

ARF5 Aux/IAA17 Complex

Summary for 6L5K

• Entry DOI: 10.2210/pdb6l5k/pdb
• Descriptor: Auxin response factor 5, Auxin-responsive protein IAA17 (3 entities in total)
• Functional Keywords: auxin, auxin response factor, aux/iaa, complex, transcription
• Biological source: Arabidopsis thaliana (Mouse-ear cress); More
• Total number of polymer chains: 2
• Total formula weight: 23740.77

Authors

Ryu, K.S.,Suh, J.Y.,Cha, S.Y.,Kim, Y.I.,Park, C.K. (deposition date: 2019-10-24, release date: 2020-09-02, Last modification date: 2023-11-22)

Primary citation

Kim, Y.,Park, C.,Cha, S.,Han, M.,Ryu, K.S.,Suh, J.Y.
Determinants of PB1 Domain Interactions in Auxin Response Factor ARF5 and Repressor IAA17.
J.Mol.Biol., 432:4010-4022, 2020

PubMed Abstract: Auxin is a plant hormone that is central to plant growth and development from embryogenesis to senescence. Auxin signaling is mediated by auxin response transcription factors (ARFs) and Aux/IAA repressors that regulate the expression of a multitude of auxin response genes. ARF and Aux/IAA proteins assemble into homomeric and heteromeric complexes via their conserved PB1 domains. Here we report the first crystal structure of the PB1 complex between ARF5 and IAA17 of Arabidopsis thaliana, which represents the transcriptionally repressed state at low auxin levels. The PB1 domains assemble in a head-to-tail manner with a backbone arrangement similar to that of the ARF5:ARF5 PB1 complex. The ARF5:IAA17 complex, however, reveals distinct points of contact that promote the ARF5:IAA17 interaction over the ARF5:ARF5 interaction. Specifically, surface charges at the interface form salt-bridges that distinguish the homomeric and heteromeric complexes, revealing common and specific interfaces between transcriptionally repressed and derepressed states. Further, the salt-bridges can be reconfigured to switch the affinity between homomeric and heteromeric complexes in an incremental manner. The complex structure combined with quantitative binding analyses would be essential for deciphering the PB1 interaction code underlying the transcriptional regulation of auxin signaling.

PubMed: 32305460
DOI: 10.1016/j.jmb.2020.04.007

Experimental method

X-RAY DIFFRACTION (2.91 Å)