All Ca2+-binding loops of light-sensitive ctenophore photoprotein berovin bind magnesium ions: The spatial structure of Mg2+-loaded apo-berovin
| Autor: | Eugene S. Vysotski, Pavel V. Natashin, Zhi-Jie Liu, Natalia P. Malikova, Mengchen Pu, Fengfeng Niu, Ludmila Burakova |
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| Rok vydání: | 2016 |
| Předmět: |
Light
Inorganic chemistry Biophysics Aequorin Photoprotein chemistry.chemical_element Molecular Dynamics Simulation Calcium Crystallography X-Ray Serine chemistry.chemical_compound Coelenterazine Animals Bioluminescence Magnesium Radiology Nuclear Medicine and imaging Amino Acid Sequence Protein Precursors Magnesium ion Thermostability Ions Binding Sites Radiation Radiological and Ultrasound Technology biology Ctenophora Protein Structure Tertiary Kinetics Luminescent Proteins Crystallography chemistry Luminescent Measurements biology.protein |
| Zdroj: | Journal of Photochemistry and Photobiology B: Biology. 154:57-66 |
| ISSN: | 1011-1344 |
| Popis: | Light-sensitive photoprotein berovin accounts for a bright bioluminescence of ctenophore Beroe abyssicola. Berovin is functionally identical to the well-studied Ca(2+)-regulated photoproteins of jellyfish, however in contrast to those it is extremely sensitive to the visible light. Berovin contains three EF-hand Ca(2+)-binding sites and consequently belongs to a large family of the EF-hand Ca(2+)-binding proteins. Here we report the spatial structure of apo-berovin with bound Mg(2+) determined at 1.75Å. The magnesium ion is found in each functional EF-hand loop of a photoprotein and coordinated by oxygen atoms donated by the side-chain groups of aspartate, carbonyl groups of the peptide backbone, or hydroxyl group of serine with characteristic oxygen-Mg(2+) distances. As oxygen supplied by the side-chain of the twelfth residue of all Ca(2+)-binding loops participates in the magnesium ion coordination, it was suggested that Ca(2+)-binding loops of berovin belong to the mixed Ca(2+)/Mg(2+) rather than Ca(2+)-specific type. In addition, we report an effect of physiological concentration of Mg(2+) on bioluminescence of berovin (sensitivity to Ca(2+), rapid-mixed kinetics, light-sensitivity, thermostability, and apo-berovin conversion into active protein). The different impact of physiological concentration of Mg(2+) on berovin bioluminescence as compared to hydromedusan photoproteins was attributed to different affinities of the Ca(2+)-binding sites of these photoproteins to Mg(2+). |
| Databáze: | OpenAIRE |
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