AN IMPROVED PROCEDURE FOR THE PREPARATION OF X-RAY-DIFFRACTION QUALITY CRYSTALS OF CYTOCHROME P450(CAM)

A procedure for the crystallization of recombinant cytochrome P450(cam ) has been developed which avoids the difficulties inherent in the gla ss-capillary free-interface diffusion method reported previously. The surface mutation, Cys334-->Ala (C334A), originally designed to prevent dimer formation and thus improve routine handling of the enzyme, faci litates crystallization by the hanging-drop vapour-diffusion technique . Crystals of (C334A)P450(cam) grow within 48 h and diffract to beyond 1.2 Angstrom at 100 K in-house on a Siemens multiwire area detector. Data have been collected from the camphor-bound form to 1.35 Angstrom.