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: 1.8 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.184 

wwPDB Validation 3D Report Full Report


This is version 1.2 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: 10.1074/jbc.M803765200
  • Primary Citation of Related Structures:  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 phycoer ...

    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, Department of Biology and Biotechnology, Ruhr-Universit├Ąt Bochum, D-44780 Bochum, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CYANOBACTERIAL PHYCOERYTHROBILIN
A, B, C, D
233Prochlorococcus phage P-SSM2Gene Names: pebS
EC: 1.3.7.6
Find proteins for Q58MU6 (Prochlorococcus phage P-SSM2)
Go to UniProtKB:  Q58MU6
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
BLA
Query on BLA

Download SDF File 
Download CCD File 
A, B, C, D
BILIVERDINE IX ALPHA
C33 H34 N4 O6
GWZYPXHJIZCRAJ-SRVCBVSDSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B, C, D
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.184 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 53.560α = 92.26
b = 67.570β = 109.07
c = 81.280γ = 106.58
Software Package:
Software NamePurpose
XSCALEdata scaling
REFMACrefinement
XDSdata reduction
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-08-05
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance