Structure of S-type Phycobiliprotein Lyase CPES from Guillardia theta

Experimental Data Snapshot

  • Resolution: 1.95 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.211 

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Insights into the Biosynthesis and Assembly of Cryptophycean Phycobiliproteins.

Overkamp, K.E.Gasper, R.Kock, K.Herrmann, C.Hofmann, E.Frankenberg-Dinkel, N.

(2014) J Biol Chem 289: 26691

  • DOI: https://doi.org/10.1074/jbc.M114.591131
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Phycobiliproteins are employed by cyanobacteria, red algae, glaucophytes, and cryptophytes for light-harvesting and consist of apoproteins covalently associated with open-chain tetrapyrrole chromophores. Although the majority of organisms assemble the individual phycobiliproteins into larger aggregates called phycobilisomes, members of the cryptophytes use a single type of phycobiliprotein that is localized in the thylakoid lumen. The cryptophyte Guillardia theta (Gt) uses phycoerythrin PE545 utilizing the uncommon chromophore 15,16-dihydrobiliverdin (DHBV) in addition to phycoerythrobilin (PEB). Both the biosynthesis and the attachment of chromophores to the apophycobiliprotein have not yet been investigated for cryptophytes. In this study, we identified and characterized enzymes involved in PEB biosynthesis. In addition, we present the first in-depth biochemical characterization of a eukaryotic phycobiliprotein lyase (GtCPES). Plastid-encoded HO (GtHo) was shown to convert heme into biliverdin IXα providing the substrate with a putative nucleus-encoded DHBV:ferredoxin oxidoreductase (GtPEBA). A PEB:ferredoxin oxidoreductase (GtPEBB) was found to convert DHBV to PEB, which is the substrate for the phycobiliprotein lyase GtCPES. The x-ray structure of GtCPES was solved at 2.0 Å revealing a 10-stranded β-barrel with a modified lipocalin fold. GtCPES is an S-type lyase specific for binding of phycobilins with reduced C15=C16 double bonds (DHBV and PEB). Site-directed mutagenesis identified residues Glu-136 and Arg-146 involved in phycobilin binding. Based on the crystal structure, a model for the interaction of GtCPES with the apophycobiliprotein CpeB is proposed and discussed.

  • Organizational Affiliation

    Physiology of Microorganisms, Faculty for Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Putative phycoerythrin lyase189Guillardia theta CCMP2712Mutation(s): 0 
Gene Names: GUITHDRAFT_191403
Find proteins for L1JFC7 (Guillardia theta (strain CCMP2712))
Explore L1JFC7 
Go to UniProtKB:  L1JFC7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupL1JFC7
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on HEZ

Download Ideal Coordinates CCD File 
B [auth A]HEXANE-1,6-DIOL
C6 H14 O2
Experimental Data & Validation

Experimental Data

  • Resolution: 1.95 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.211 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 80.83α = 90
b = 116.58β = 90
c = 58.75γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
German Research FoundationGermanyFR1687/6-1
Studienstiftung des Deutschen VolkesGermany--

Revision History  (Full details and data files)

  • Version 1.0: 2014-08-13
    Type: Initial release
  • Version 1.1: 2014-08-20
    Changes: Database references
  • Version 2.0: 2017-09-06
    Changes: Atomic model, Author supporting evidence, Derived calculations, Refinement description
  • Version 2.1: 2017-10-18
    Changes: Data collection