12th International Symposium on Bioluminescence & Chemiluminescence

Symposium abstracts:

The crystal structure of the calcium-regulated photoprotein obelin from Obelia geniculata

Deng, Lu¹, Vysotski, Eugene^{2, 3}, Liu, Zhi-Jie², Markova, Svetlana^{2, 3}, Lee, John², Rose, John², Wang, Bi-Cheng²

1. Department of Chemistry, University of Georgia, USA
2. Department of Biochemistry and Molecular Biology, University of Georgia, USA
3. Institute of Biophysics RAS, SB, Krasnoyarsk, Russia

Crystals of recombinant obelin, originating from Obelia geniculata, were obtained by the hanging-drop vapor-diffusion technique. A complete diffraction data set to 1.8 Å resolution has been collected at 100 K, using 1.0 Å X-rays at a synchrotron source. The space group is P2₁2₁2₁ with unit-cell dimensions a = 33.502 Å, b = 67.823 Å, c = 69.209 Å. The crystal structure has been determined by the molecular replacement method using the structure of obelin from O. longissima as a search model and refined to 1.82 Å with an R factor of 21.2%. Peroxide substitution at the C2-position of the coelenterazine is confirmed by the presence of electron density corresponding to two oxygen atoms. This density is equally as intense as the individual atoms of the coelenterazine ligand, in contrast with the results of other calcium-regulated photoproteins.

Supported by ONR, N 00014-99-1-0414, and RAS, 99-04-48452.

This is a preprint of an article accepted for publication in Luminescence: Copyright 2001 John
Wiley & Sons, Ltd (Wiley website)