2VCK

Structure of Phycoerythrobilin Synthase PebS from the Cyanophage P-SSM2 in Complex with the bound Substrate Biliverdin IXa


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.187 

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Phycoerythrobilin Synthase (Pebs) of a Marine Virus: Crystal Structures of the Biliverdin Complex and the Substrate-Free Form.

Dammeyer, T.Hofmann, E.Frankenberg-Dinkel, N.

(2008) J Biol Chem 283: 27547

  • DOI: https://doi.org/10.1074/jbc.M803765200
  • Primary Citation of Related Structures:  
    2VCK, 2VCL, 2VGR

  • PubMed Abstract: 

    The reddish purple open chain tetrapyrrole pigment phycoerythrobilin (PEB; A(lambdamax) approximately 550 nm) is an essential chromophore of the light-harvesting phycobiliproteins of most cyanobacteria, red algae, and cryptomonads. The enzyme phycoerythrobilin synthase (PebS), recently discovered in a marine virus infecting oceanic cyanobacteria of the genus Prochlorococcus (cyanophage PSSM-2), is a new member of the ferredoxin-dependent bilin reductase (FDBR) family. In a formal four-electron reduction, the substrate biliverdin IXalpha is reduced to yield 3Z-PEB, a reaction that commonly requires the action of two individual FDBRs. The first reaction catalyzed by PebS is the reduction of the 15,16-methine bridge of the biliverdin IXalpha tetrapyrrole system. This reaction is exclusive to PEB biosynthetic enzymes. The second reduction site is the A-ring 2,3,3(1),3(2)-diene system, the most common target of FDBRs. Here, we present the first crystal structures of a PEB biosynthetic enzyme. Structures of the substrate complex were solved at 1.8- and 2.1-A resolution and of the substrate-free form at 1.55-A resolution. The overall folding revealed an alpha/beta/alpha-sandwich with similarity to the structure of phycocyanobilin:ferredoxin oxidoreductase (PcyA). The substrate-binding site is located between the central beta-sheet and C-terminal alpha-helices. Eight refined molecules with bound substrate, from two different crystal forms, revealed a high flexibility of the substrate-binding pocket. The substrate was found to be either in a planar porphyrin-like conformation or in a helical conformation and is coordinated by a conserved aspartate/asparagine pair from the beta-sheet side. From the alpha-helix side, a conserved highly flexible aspartate/proline pair is involved in substrate binding and presumably catalysis.


  • Organizational Affiliation

    Physiology of Microorganisms, Ruhr-Universität Bochum, D-44780 Bochum, Germany.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CYANOBACTERIAL PHYCOERYTHROBILIN
A, B, C, D
233Prochlorococcus phage P-SSM2Mutation(s): 0 
EC: 1.3.7.6
UniProt
Find proteins for Q58MU6 (Prochlorococcus phage P-SSM2)
Explore Q58MU6 
Go to UniProtKB:  Q58MU6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ58MU6
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.187 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.56α = 92.26
b = 67.57β = 109.07
c = 81.28γ = 106.58
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XSCALEdata scaling
MOLREPphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-08-05
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2019-05-08
    Changes: Data collection, Derived calculations, Experimental preparation, Other
  • Version 1.4: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description