    1.14.14.23 | wild-type CYP7A1 in the ligand-free state, structure-based mutation T104L in the B' helix, corresponding to the nonpolar residue of CYP7B1, is used to obtain crystals of complexes with cholest-4-en-3 -one and with cholesterol oxidation product 7-ketocholesterol, hanging drop vapor diffusion method, mixing 0f 0.001 ml of protein solution with 0.001 ml of reservoir solution containing 0.1 M sodium chloride, 0.1 M trisodium citrate, pH 5.5, and 20% PEG 400, 18°C, to obtain a complex with cholest-4-en-3-one, a T104L mutant is used, and the crystals are grown in conditions containing 0.1 M MES, pH 6.0, and 18% PEG 550 monomethylether and soaked with 20% glycerol. For the T104L mutant-7KCh complex, crystals are grown in 0.1 M sodium chloride, 0.1 M tri-sodium citrate, pH 5.6, and 20% PEG 400, room temperature, X-ray diffraction structure determination and analysis at 1.90-2.75 A resolution |
