5TUW

Crystal structure of Orange Carotenoid Protein with partial loss of 3'OH Echinenone chromophore


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.302 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.185 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Photoactivation mechanism of a carotenoid-based photoreceptor.

Bandara, S.Ren, Z.Lu, L.Zeng, X.Shin, H.Zhao, K.H.Yang, X.

(2017) Proc. Natl. Acad. Sci. U.S.A. 114: 6286-6291

  • DOI: 10.1073/pnas.1700956114
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Photoprotection is essential for efficient photosynthesis. Cyanobacteria have evolved a unique photoprotective mechanism mediated by a water-soluble carotenoid-based photoreceptor known as orange carotenoid protein (OCP). OCP undergoes large conforma ...

    Photoprotection is essential for efficient photosynthesis. Cyanobacteria have evolved a unique photoprotective mechanism mediated by a water-soluble carotenoid-based photoreceptor known as orange carotenoid protein (OCP). OCP undergoes large conformational changes in response to intense blue light, and the photoactivated OCP facilitates dissipation of excess energy via direct interaction with allophycocyanins at the phycobilisome core. However, the structural events leading up to the OCP photoactivation remain elusive at the molecular level. Here we present direct observations of light-induced structural changes in OCP captured by dynamic crystallography. Difference electron densities between the dark and illuminated states reveal widespread and concerted atomic motions that lead to altered protein-pigment interactions, displacement of secondary structures, and domain separation. Based on these crystallographic observations together with site-directed mutagenesis, we propose a molecular mechanism for OCP light perception, in which the photochemical property of a conjugated carbonyl group is exploited. We hypothesize that the OCP photoactivation starts with keto-enol tautomerization of the essential 4-keto group in the carotenoid, which disrupts the strong hydrogen bonds between the bent chromophore and the protein moiety. Subsequent structural changes trapped in the crystal lattice offer a high-resolution glimpse of the initial molecular events as OCP begins to transition from the orange-absorbing state to the active red-absorbing state.


    Organizational Affiliation

    Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Orange carotenoid-binding protein
A, B, C, D, E, F
323Synechocystis sp. (strain PCC 6803 / Kazusa)Mutation(s): 0 
Find proteins for P74102 (Synechocystis sp. (strain PCC 6803 / Kazusa))
Go to UniProtKB:  P74102
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EQ3
Query on EQ3

Download SDF File 
Download CCD File 
A, B, C, D, E, F
(3'R)-3'-hydroxy-beta,beta-caroten-4-one
3'-Hydroxyechinenone, 3'-OH-Echinenone
C40 H54 O2
ZRCXVNZZDQGBQT-BANQPSJHSA-N
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, C, E
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.302 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.185 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 82.947α = 89.79
b = 82.914β = 89.91
c = 87.438γ = 60.04
Software Package:
Software NamePurpose
PHENIXphasing
HKL-2000data scaling
PHENIXrefinement
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Eye InstituteUnited StatesR01EY024363

Revision History 

  • Version 1.0: 2017-06-07
    Type: Initial release
  • Version 1.1: 2017-06-14
    Type: Database references
  • Version 1.2: 2017-06-21
    Type: Database references
  • Version 1.3: 2017-09-20
    Type: Author supporting evidence