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. 2011 May;67(Pt 5):463-70.
doi: 10.1107/S0907444911008754. Epub 2011 Apr 7.

Pi sampling: a methodical and flexible approach to initial macromolecular crystallization screening

Fabrice Gorrec  1 , Colin M Palmer, Guillaume Lebon, Tony Warne
Affiliations

Pi sampling: a methodical and flexible approach to initial macromolecular crystallization screening

Fabrice Gorrec et al. Acta Crystallogr D Biol Crystallogr. 2011 May.

Abstract

The Pi sampling method is derived from the incomplete factorial approach to macromolecular crystallization screen design. The resulting `Pi screens' have a modular distribution of a given set of up to 36 stock solutions. Maximally diverse conditions can be produced by taking into account the properties of the chemicals used in the formulation and the concentrations of the corresponding solutions. The Pi sampling method has been implemented in a web-based application that generates screen formulations and recipes. It is particularly adapted to screens consisting of 96 different conditions. The flexibility and efficiency of Pi sampling is demonstrated by the crystallization of soluble proteins and of an integral membrane-protein sample.

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Figures

Figure 1
Figure 1
Pi sampling: combinations of stock solutions from three different sets (see also http://pisampler.mrc-lmb.cam.ac.uk/).
Figure 2
Figure 2
Pi sampling: combinations of the stock solutions in a 96-condition plate layout (well A1 is at the top left corner). Each solution of set 1 (ID 1–12) is seen in the eight conditions forming a column of the plate. The Δ values of set 1 increase from left to right in the screen layout. The positions of the solutions A–L (set 2) shift across five columns and down one row (Δ values not represented). The positions of solutions M–X (set 3) shift across ten columns and down one row. Gradients of concentration for sets 2 and 3 are represented on the left and right, respectively.
Figure 3
Figure 3
Crystals of A2AR-GL31 obtained with the Pi-PEG screen (Table 4 ▶) and an example of a corresponding diffraction pattern.
See this image and copyright information in PMC

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