Selecting temperature for protein crystallization screens using the temperature dependence of the second virial coefficient

Protein crystals usually grow at a preferable temperature which is however not known for a new protein. This paper reports a new approach for determination of favorable crystallization temperature, which can be adopted to facilitate the crystallization screening process. By taking advantage of the correlation between the temperature dependence of the second virial coefficient (B₂₂) and the solubility of protein, we measured the temperature dependence of B₂₂ to predict the temperature dependence of the solubility. Using information about solubility versus temperature, a preferred crystallization temperature can be proposed. If B₂₂ is a positive function of the temperature, a lower crystallization temperature is recommended; if B₂₂ shows opposite behavior with respect to the temperature, a higher crystallization temperature is preferred. Otherwise, any temperature in the tested range can be used.