Colloidal approach analysis of the Marseille protein crystallization database for protein crystallization strategies

We have created a new online crystallization database, the Marseille Protein Crystallization Database (MPCD) [Charles et al. 2006, Acta Crystallogr. D62, 1311-1318], that includes information on macromolecules (name, pI, MW, number of subunits), crystallization conditions, methods and additives used, in standardized and tabulated form. It is freely accessible via http:// www.crmcn.univ-mrs.fr/mpcd/ and allows users to choose their own crystallization parameters, to create tables for further physicochemical analysis, and to enter new protein and crystallization conditions to supplement this database. The MPCD has previously been analyzed by Charles et al., by examining first each parameter independently to distinguish relevant data (i.e., PH, pI, nature and percentage of polymer) from statistical data (i.e., temperature, nature of salt). In the present paper, we analyze the database in regard to scattering studies and crystal growth experiments performed on various model systems. Some general trends of crystallization parameters are highlighted in correlation with results obtained from the study both of macromolecular interactions in solution using scattering techniques and of crystallization mechanisms using optical microscopy, to give some simple guidelines for biocrystallization. The main result is the synergistic effect of salt and polyethylene glycol observed both on interactions in solution, measured by scattering techniques and from the MPCD analysis.