How do I translate from microbatch-under-oil to vapor diffusion?
First, ask yourself if this is really necessary. Although you may prefer other methods, there are some real advantages to using the same crystallization method for screening and optimization. There is information available on converting from microbatch-under-oil to vapor diffusion experiments available in the literature [Acta Cryst. D54, 8-15 (1998)]. A few basic concepts: When you set up a batch experiment by combining equal volumes of protein and cocktail solution, you are diluting any solute not contained at the same concentration in both solutions. For example, if the protein concentration was 10 mg/ml in the stock solution, it will be 5 mg/ml in the batch crystallization experiment. Ideally, batch experiments will not dehydrate. The starting and final concentrations of the protein in the batch crystallization experiment remain at 5 mg/ml, unless a phase change (e.g., crystallization, precipitation) occurs and drives some of the protein from the solution state. In the case of a vap
