Crystallographic analyses of lysozyme and collagenase microgravity grown crystals versus ground controls

Hen egg white lysozyme and collagenase from Hypoderma lineatum larvae have been used as model proteins of known physical and chemical properties to study the influence of microgravity on crystal quality. This was performed using the Advanced Protein Crystallization Facility instrument during two successive missions of the US Space Shuttle. Lysozyme crystals were grown during the SpaceHab-01 mission and are compared with those obtained during the six months Eureca mission using the Protein Crystallization Facility instrument. Collagenase crystals were produced during the IML-2 mission. Space grown crystals as well as grounds controls were analyzed using synchrotron radiation to assess their diffraction limits. For lysozyme crystals, a large number of ground and microgravity grown crystals were analyzed and showed nearly equivalent maximum resolution (best one is 1.3 Angstrom). Collagenase crystals from IML-2, although presenting a marginal increase of resolution (1.7 Angstrom), display a better signal to noise ratio than ground crystals.