From phasing to structure refinement in-house: Cr/Cu dual-wavelength system and a loopless free crystal-mounting method

The practical applicability of in‐house structure determination using Cr Kα X‐rays (2.29 Å) and a loopless free crystal‐mounting method was examined using five novel proteins. Proteins from 9.6 to 84 kDa have been solved using this method without any derivatization. In all cases, more than 90% of structures were constructed automatically with side chains by use of the Cr SAD method. The free crystal‐mounting technique increases the accuracy of the anomalous differences between Bijvoet mates and makes the in‐house single‐wavelength SAD method with a Cr Kα X‐ray source a very useful tool for high‐throughput structure determination. In addition, a Cr/Cu dual‐wavelength system makes it possible to perform structure analysis from phasing to refinement of the structure in‐house.