Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 22.73 kDa 
• Atom Count: 1,856 
• Modelled Residue Count: 194 
• Deposited Residue Count: 195 
• Unique protein chains: 1

 1EL4

STRUCTURE OF THE CALCIUM-REGULATED PHOTOPROTEIN OBELIN DETERMINED BY SULFUR SAS

• PDB DOI: 10.2210/pdb1EL4/pdb

• Classification: LUMINESCENT PROTEIN
• Organism(s): Obelia longissima
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2000-03-13 Released: 2001-03-13 
• Deposition Author(s): Liu, Z.J., Vysotski, E.S., Rose, J., Lee, J., Wang, B.C.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.73 Å
• R-Value Free: 0.205 
• R-Value Work: 0.188 
• R-Value Observed: 0.191 

Literature

Structure of the Ca2+-regulated photoprotein obelin at 1.7 A resolution determined directly from its sulfur substructure.

Liu, Z.J., Vysotski, E.S., Chen, C.J., Rose, J.P., Lee, J., Wang, B.C.

(2000) Protein Sci 9: 2085-2093

• PubMed: 11152120 
• DOI: 10.1110/ps.9.11.2085
• Primary Citation of Related Structures:  
  1EL4


• PubMed Abstract: 
  

The crystal structure of the photoprotein obelin (22.2 kDa) from Obelia longissima has been determined and refined to 1.7 A resolution. Contrary to the prediction of a peroxide, the noncovalently bound substrate, coelenterazine, has only a single oxygen atom bound at the C2-position. The protein-coelenterazine 2-oxy complex observed in the crystals is photo-active because, in the presence of calcium ion, bioluminescence emission within the crystal is observed. This structure represents only the second de novo protein structure determined using the anomalous scattering signal of the sulfur substructure in the crystal. The method used here is theoretically different from that used for crambin in 1981 (4.72 kDa) and represents a significant advancement in protein crystal structure determination.

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Related Citations: 

• Preparation and preliminary study of crystals of the recombinant calcium-regulated photoprotein obelin from the bioluminescent hydroid obelia longissima
  Vysotski, E.S., Liu, Z.J., Rose, J., Wang, B.C., Lee, J.
  (1999) Acta Crystallogr D Biol Crystallogr 55: 1965

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Organizational Affiliation: 

Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
OBELIN	A	195	Obelia longissima	Mutation(s): 0
UniProt
Find proteins for Q27709 (Obelia longissima) Explore Q27709  Go to UniProtKB:  Q27709

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CTZ	C [auth A]	C2-HYDROXY-COELENTERAZINE C26 H21 N3 O4 ULLMMKZQNNBLRN-SANMLTNESA-N
CL	B [auth A]	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.73 Å
• R-Value Free: 0.205 
• R-Value Work: 0.188 
• R-Value Observed: 0.191 
• Space Group: P 6₂

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 81.562	α = 90
b = 81.562	β = 90
c = 86.088	γ = 120

Software Package:

Software Name	Purpose
SOLVE	phasing
CNS	refinement
HKL-2000	data reduction
HKL-2000	data scaling
ISAS	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 2001-03-13 
Deposition Author(s): Liu, Z.J., Vysotski, E.S., Rose, J., Lee, J., Wang, B.C.

Revision History  

• Version 1.0: 2001-03-13
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance