X-RAY DIFFRACTION |
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293 |
Crystallization assays were set up following the sitting-drop vapor diffusion method at the joint IBMB/IRB Automated Crystallography Platform of Barcelona Science Park. A Tecan robot (Tecan Trading) was used to prepare reservoir solutions, and a Cartesian Microsys 4000 XL robot (Genomic Solutions) or a Phoenix nanodrop robot (Art Robbins Instruments) dispensed nanocrystallization drops on 96x2-well Swissci Polystyrene MRC Crystallization Plates (Molecular Dimensions). Plates were stored at 4 or 20 degrees in thermostatic crystal farms (Bruker AXS). The astacin-hFB complex only crystallized after incubating the inhibitor (at 7.5 mg/mL) with six-fold molar excess of the peptidase in 10 mM Tris-HCl, 140 mM sodium chloride, pH 6.8. Crystals were obtained at 20 degrees in 200 nL:100 nL drops with protein complex solution and 20 percent (w/v) polyethylene glycol 3,350, 0.2 M sodium tartrate dibasic as reservoir solution. |