Primary Citation of Related Structures: 1SL7, 1SL8
PubMed Abstract:
The crystal structures of calcium-loaded apo-aequorin and apo-obelin have been determined at resolutions 1.7A and 2.2 A, respectively. A calcium ion is observed in each of the three EF-hand loops that have the canonical calcium-binding sequence, and each is coordinated in the characteristic pentagonal bipyramidal configuration ...
The crystal structures of calcium-loaded apo-aequorin and apo-obelin have been determined at resolutions 1.7A and 2.2 A, respectively. A calcium ion is observed in each of the three EF-hand loops that have the canonical calcium-binding sequence, and each is coordinated in the characteristic pentagonal bipyramidal configuration. The calcium-loaded apo-protein retain the same compact scaffold and overall fold as the unreacted photoproteins containing the bound substrate, 2-hyroperoxycoelenterazine, and also the same as the Ca2+-discharged obelin bound with product, coleneteramide. Nevertheless, there are easily discerned shifts in both helix and loop regions, and the shifts are not the same between the two proteins. It is suggested that these photoproteins to sense Ca2+ concentration transients and to produce their bioluminescence response on the millisecond timescale. A mechanism of intrastructural transmission of the calcium signal is proposed.
Related Citations:
Structure of the Ca2+-regulated photoprotein obelin at 1.7 resolution determined directly from its sulfur substructure Liu, Z.-J., Vysotski, E.S., Chen, C.-J., Rose, J., Lee, J., Wang, B.-C. (2000) Protein Sci 9: 2085
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
Structural basis for the emission of violet bioluminescence from
a W92F obelin mutant Deng, L., Vysotski, E.S., Liu, Z.-J., Markova, S.V., Malikova, N.P., Lee, J., Rose, J., Wang, B.-C. (2001) FEBS Lett 506: 281
Violet Bioluminescence and Fast Kinetics from W92F Obelin: Structure-Based
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Atomic resolution structure of obelin: Soaking with calcium enhances electron density of the second oxygen atom substituted at the C2-position of coelenterazine Liu, Z.-J., Vysotski, E.S., Deng, L., Lee, J., Rose, J., Wang, B.-C. (2003) Biochem Biophys Res Commun 311: 433
Preparation and X-ray Crystallographic Analysis of the Ca2+-discharged Photoprotein Obelin Deng, L., Markova, S.V., Vysotski, E.S., Liu, Z.-J., Lee, J., Rose, J., Wang, B.-C. () To be published --: --
Organizational Affiliation:
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
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