Nanovolume optimization of protein crystal growth using the microcapillary protein crystallization system

The Microcapillary Protein Crystallization System (MPCS) is a microfluidic, plug‐based crystallization technology that generates X‐ray diffraction‐ready protein crystals in nanolitre volumes. In this study, 28 out of 29 (93%) proteins crystallized by traditional vapor diffusion experiments were successfully crystallized by chemical gradient optimization experiments using the MPCS technology. In total, 90 out of 120 (75%) protein/precipitant combinations leading to initial crystal hits from vapor diffusion experiments were successfully crystallized using MPCS technology. Many of the resulting crystals produced high‐quality X‐ray diffraction data, and six novel protein structures that were derived from crystals harvested from MPCS CrystalCards are reported.