2HPS: Crystal Structure Of Coelenterazine-binding Protein From Renilla Muelleri

Bioluminescence in the sea pansy Renilla involves two distinct proteins, a Ca2+-triggered coelenterazine-binding protein (CBP), and Renilla luciferase. CBP contains one tightly bound coelenterazine molecule, which becomes available for reaction with luciferase and O2 only subsequent to Ca2+ binding. CBP belongs to the EF-hand superfamily of Ca2+-binding proteins and contains three "EF-hand" Ca2+-binding sites. The overall spatial structure of recombinant selenomethionine-labeled CBP determined at 1.7 A, is found to approximate the protein scaffold characteristic of the class of Ca2+-regulated photoproteins. Photoproteins however, catalyze molecular oxygen addition to coelenterazine producing a 2-hydroperoxycoelenterazine intermediate, which is stabilized within the binding cavity in the absence of Ca2+. Addition of Ca2+ triggers the bioluminescence reaction. However in CBP this first step of oxygen addition is not allowed. The different amino acid environments and hydrogen bond interactions within the binding cavity, are proposed to account for the different properties of the two classes of proteins.
PDB ID: 2HPSDownload
MMDB ID: 43866
PDB Deposition Date: 2006/7/17
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.72  Å
Source Organism:
Similar Structures:
Biological Unit for 2HPS: monomeric; determined by author
Molecular Components in 2HPS
Label Count Molecule
Protein (1 molecule)
Coelenterazine-binding Protein With Bound Coelenterazine
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB