A straightforward and robust method for introducing human hair as a nucleant into high throughput crystallization trials

Growing X-ray grade crystals of a specific protein is a process of trial and error. Usually, hundreds or even thousands of conditions are screened in order to identify useful crystallization conditions. Heterogeneous nucleants have been shown to increase the success rate of crystallization trials, and (human) hair has previously been identified as a promising nucleant. Here, we describe and evaluate a method for preparing crystallization plates that are locally coated with fragments of human hair, allowing automated, high-throughput crystallization trials in a fashion that is entirely compatible with standard hanging or sitting drop crystallization techniques. We assessed the effect of these nucleants on the crystallization of 11 different proteins in more than 4000 crystallization trials. We found additional crystallization conditions for 10 out of 11 proteins when using the standard JCSG+ screen (96 different conditions). In total, 34 additional crystallization conditions could be identified (13.1% of t...