5ZAB
Crystal structure of cf3-aequorin
Summary for 5ZAB
| Entry DOI | 10.2210/pdb5zab/pdb |
| Descriptor | Aequorin-2, (2S)-8-benzyl-2-hydroperoxy-6-(4-hydroxyphenyl)-2-{[4-(trifluoromethyl)phenyl]methyl}imidazo[1,2-a]pyrazin-3(2H)-one (3 entities in total) |
| Functional Keywords | semi-synthetic aequorin, luminescent protein |
| Biological source | Aequorea victoria (Jellyfish) |
| Total number of polymer chains | 16 |
| Total formula weight | 368825.25 |
| Authors | Inouye, S.,Tomabechi, Y.,Sekine, S.I.,Shirouzu, M.,Hosoya, T. (deposition date: 2018-02-07, release date: 2018-06-06, Last modification date: 2023-11-22) |
| Primary citation | Inouye, S.,Tomabechi, Y.,Hosoya, T.,Sekine, S.I.,Shirouzu, M. Slow luminescence kinetics of semi-synthetic aequorin: expression, purification and structure determination of cf3-aequorin. J. Biochem., 164:247-255, 2018 Cited by PubMed Abstract: cf3-Aequorin is one of the semi-synthetic aequorins that was produced by replacing 2-peroxycoelenterazine (CTZ-OOH) in native aequorin with a 2-peroxycoelenterazine analog, and it was prepared using the C2-modified trifluoromethyl analog of coelenterazine (cf3-CTZ) and the histidine-tagged apoaequorin expressed in Escherichia coli cells. The purified cf3-aequorin showed a slow luminescence pattern with half-decay time of maximum intensities of luminescence of 5.0 s. This is much longer than that of 0.9 s for native aequorin, and its luminescence capacity was estimated to be 72.8% of that of native aequorin. The crystal structure of cf3-aequorin was determined at 2.15 Å resolution. The light source of 2-peroxytrifluoromethylcoelenterazine (cf3-CTZ-OOH) was stabilized by the hydrogen-bonding interactions at the C2-peroxy moiety and the p-hydroxy moiety at the C6-phenyl group. In native aequorin, three water molecules contribute to stabilizing CTZ-OOH through hydrogen bonds. However, cf3-aequorin only contained one water molecule, and the trifluoromethyl moiety at the C2-benzyl group of cf3-CTZ-OOH interacted with the protein by van der Waals interactions. The slow luminescence kinetics of cf3-aequorin could be explained by slow conformational changes due to the bulkiness of the trifluoromethyl group, which might hinder the smooth cleavage of hydrogen bonds at the C2-peroxy moiety after the binding of Ca2+ to cf3-aequorin. PubMed: 29796619DOI: 10.1093/jb/mvy049 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.147 Å) |
Structure validation
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