E0054

Optimizing Liquid Handling Parameters for Protein Crystallography. Marc N. Feiglin¹, Bill Edstrom², Natalie Joseph³, Regula Stoerrlein⁴, Carsten Aprill⁴, Andrew Vessey⁵, Rick Luedke⁵, John Hunt², ¹Tecan Group, Männedorf Switzerland, ²Columbia Univ., New York, NY, ³Tecan UK, Reading, UK, ⁴Tecan Schweiz, Männedorf Switzerland, ⁵Tecan US, RTP, NC.

Discovering the appropriate conditions to encourage the formation of protein crystals can be a tedious and frustrating endeavor. In recent years, crystallographers have begun exploring instrumentation and software approaches to streamline the process. Many have looked to automated liquid handlers, a staple in other fields of life sciences research, to automate the generation of exploratory buffer sets from stock solutions, and to set up multi-well crystallography plates. Automating this part of the process offers the appealing advantages of relieving the tedium of manual pipetting, and improving the long-term reproducibility of liquid handling.

Crystallization experiments and solutions place several unique demands on automated liquid handlers. Some stocks and buffers include highly viscous materials such as polyethylene glycol, while others contain very non-viscous components such as iso-propanol. Furthermore, buffer set creation requires accurate pipetting of milliliter volumes, while final experimental setup requires accuracy and precision in the nanoliter range. Most automated liquid handlers come configured with default settings for liquid classes (the optimal parameters for pipetting a certain volume range of a given solution), but few if any of a liquid handler’s defaults will provide satisfactory pipetting of crystallization buffers. Optimizing pipetting conditions for each solution and situation can be a challenging experiment in itself, and can test the limits of commercially available liquid handlers.

This poster details the work performed to optimize liquid handling parameters for protein crystallization experiments on a Tecan Genesis automated liquid handler. Data is presented on the optimization of Tecan Genesis liquid classes for solutions such as 50% PEG 10,000 which are used to create custom screening kits. These data show results comparable to those achieved by careful hand-pipetting. Liquid classes have also been developed for pipetting screening kits, such as the Hampton Research Crystal Screen™, when setting up protein crystallography experiments. These data have been collected for a range of tip options on the Tecan Genesis and they demonstrate commendable performance for crystallization experiments.