Figure 1.

Concentration range of precipitant in the reservoir solution in the presence of additives in which hemoglobin crystals were formed. Hanging droplets were made by mixing 1 µl of 40 mg ml⁻¹ hemoglobin solution with 1 µl of reservoir solution. The reservoir solutions contain 5.0–40.0% PEG 3350 at 2.5% intervals, 0.2 M additives and 0.1 M sodium phosphate (pH 6.5). The bars show the precipitant concentration range in which crystals were formed.