Crystallization and preliminary X-ray analysis of recombinant full-length human m-calpain

m-Calpain constitutes the prototype of the superfamily of neutral calcium-a ctivated cysteine proteinases. It is a heterodimer consisting of an 80 and a 30 kDa subunit. Recombinant full-length human m-calpain has been crystall ized using macro-seeding techniques and vapour-diffusion methods. Two diffe rent monoclinic crystal forms (space group P2(1)) were obtained from a solu tion containing polyethylene glycol (M-w = 10 000) as a pecipitating agent. Complete data sets have been collected to 2.3 and 3.0 Angstrom resolution using cryo-cooling conditions and synchrotron radiation. The unit-cell para meters are a = 64.86, b = 133.97, c = 78.00 Angstrom, beta = 102.43 degrees and a = 51.80, b = 171.36, c = 64.66 Angstrom, beta = 94.78 degrees, respe ctively. The V-m values indicate that there is one heterodimer in each asym metric unit.