CRYSTALLIZATION AND PRELIMINARY-X-RAY DIFFRACTION STUDIES OF METHYL-COENZYME-M REDUCTASE FROM METHANOBACTERIUM-THERMOAUTOTROPHICUM

Methyl-coenzyme M reductase isoenzyme I from the methanogenic Archaeon , Methanobacterium thermoautotrophicum (strain Marburg), was crystalli zed by vapor diffusion methods, Crystal form M obtained with 2-methyl- 2,4-pentanediol as the precipitant displayed space group P2(1), with u nit cell parameters of a=83.2 Angstrom, b=117.4 Angstrom, c=125.1 Angs trom, and beta=92.6 degrees, and diffracted at better than 2.8 Angstro m resolution, Crystal form P grown from polyethylene glycol 400 belong ed to space group P2(1), and had unit cell parameters of a=83.1 Angstr om, b=120.2 Angstrom, c=123.1 Angstrom, and beta=91.7 degrees, diffrac ting at least to 1.7 Angstrom resolution, Both crystal forms have one molecule per asymmetric unit and are suitable for X-ray structure anal ysis.