PDBsum entry 6qtt

Plant protein

PDB id: 6qtt

Contents

Protein chain

307 a.a.

Ligands

LEU-LEU-MET-VAL-PRO-ASP-MET-TYR

MLI ×2

GOL

Waters ×239

PDB id:

6qtt

Name:

Plant protein

Title:

Crystal structure of an arabidopsis wd40 domain in complex with a transcription factor homolog

Structure:

E3 ubiquitin-protein ligase cop1. Chain: a. Synonym: constitutive photomorphogenesis protein 1,ring-type e3 ubiquitin transferase cop1. Engineered: yes. Transcription factor hy5-like. Chain: b. Synonym: hy5 homolog,bzip transcription factor 64,atbzip64. Engineered: yes

Source:

Arabidopsis thaliana. Mouse-ear cress. Organism_taxid: 3702. Gene: cop1, at2g32950, t21l14.11. Expressed in: spodoptera frugiperda. Expression_system_taxid: 7108. Synthetic: yes. Thale cress. Organism_taxid: 3702

Resolution:

1.51Å R-factor: 0.155 R-free: 0.185

Authors:

M.Hothorn,K.Lau

Key ref:

K.Lau et al. (2019). Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs. EMBO J, 38, e102140. PubMed id: 31304983 DOI: 10.15252/embj.2019102140

Date:

25-Feb-19 Release date: 10-Jul-19

Protein chain

P43254  (COP1_ARATH) -  E3 ubiquitin-protein ligase COP1 from Arabidopsis thaliana

Seq: 675 a.a.

Struc: 307 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.2.3.2.27 - RING-type E3 ubiquitin transferase.
• Reaction: S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N₆- ubiquitinyl-[acceptor protein]-L-lysine

DOI no: 10.15252/embj.2019102140

EMBO J 38:e102140 (2019)

PubMed id: 31304983

Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs.

K.Lau, R.Podolec, R.Chappuis, R.Ulm, M.Hothorn.

ABSTRACT

Plants sense different parts of the sun's light spectrum using distinct photoreceptors, which signal through the E3 ubiquitin ligase COP1. Here, we analyze why many COP1-interacting transcription factors and photoreceptors harbor sequence-divergent Val-Pro (VP) motifs that bind COP1 with different binding affinities. Crystal structures of the VP motifs of the UV-B photoreceptor UVR8 and the transcription factor HY5 in complex with COP1, quantitative binding assays, and reverse genetic experiments together suggest that UVR8 and HY5 compete for COP1. Photoactivation of UVR8 leads to high-affinity cooperative binding of its VP motif and its photosensing core to COP1, preventing COP1 binding to its substrate HY5. UVR8-VP motif chimeras suggest that UV-B signaling specificity resides in the UVR8 photoreceptor core. Different COP1-VP peptide motif complexes highlight sequence fingerprints required for COP1 targeting. The blue-light photoreceptors CRY1 and CRY2 also compete with transcription factors for COP1 binding using similar VP motifs. Thus, our work reveals that different photoreceptors and their signaling components compete for COP1 via a conserved mechanism to control different light signaling cascades.