Automated protein crystallization and a new crystal form of a subtilisin:eglin complex

A procedure is described for automating labour-intensive stepsof the ‘hanging drop’ protein crystallization method.An automatic sample changer is employed to fill the wells ina multi-well plate so that concentration gradients in variouscomponents are obtained. The sample changer is also used forpreparing droplets on a second multi-well plate. Subse quently,this second plate is manually turned around and placed on topof the first multi-well plate such that a large number of chamberswith different conditions is obtained simultaneously. Duringinitial trials a new crystal form of a subtilisin:eglin complexwas obtained. The crystals have space group P2₁ contain twoenzyme inhibitor complexes per asymmetric unit and diffractbeyond 2.2 Å.