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5 and concentrated using centrifugal concentrators (Sartorius) prior to crystallization trials. LmTBCC lacks tryptophan, so chromatograms were obtained at both 215 and 280?nm and the protein concentration was determined by measurement of the absorbance at 595?nm using Coomassie (Bradford) protein-assay reagent (Thermo Fisher Scientific) with bovine serum albumin as a reference. Protein mass was verified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry [http://www.selleckchem.com/products/AZD2281(Olaparib).html Olaparib research buy] (MALDI-TOF; University of Dundee Proteomics Facility) and sample purity was assessed by SDS�CPAGE. 2.2. Crystallization ? The lower abundance, higher molecular-weight sample did not produce any crystals. [http://www.selleckchem.com/products/Y-27632.html this website] The other sample of full-length LmTBCA gave highly ordered crystals in hanging-drop vapour-diffusion experiments when a protein solution at 4?mg?ml?1 in 50?mM Tris�CHCl pH 7.5, 100?mM NaCl was mixed with an equal volume of reservoir solution [0.2?M (NH4)2HPO4, 1.6?M ammonium sulfate]. Crystals with typical dimensions of 1.0 �� 0.2 �� 0.2?mm appeared within 1�C3?d at 291?K. Isomorphous (Table 1 ?) but much smaller SeMet-LmTBCA crystals were grown using the same approach with the protein at a concentration of 3.8?mg?ml?1 and using a reservoir solution consisting of 0.3?M LiCl, 1.0?M ammonium sulfate. Table 1 Crystallographic statistics 2.3. X-ray data collection and processing, structure determination and refinement ? Crystals were cryoprotected in mother liquor supplemented with 25%(v/v) glycerol and were then flash-cooled in liquid nitrogen before in-house screening and characterization using a Rigaku MicroMax-007 HF rotating-anode source equipped with a Saturn 944 HG+ CCD detector with the sample maintained at 100?K. Diffraction data were subsequently collected from both native and SeMet-derivative crystals on beamline ID23-2 at the European Synchrotron Radiation Facility (ESRF) using a MAR Mosaic [https://en.wikipedia.org/wiki/Bepotastine bepotastine] 225 CCD detector. This beamline has a fixed wavelength of 0.8726??, which is a higher energy than that of the optimum selenium f��� edge, but still sufficient to give values for f�� and f��� of approximately ?1.2 and 3.0, respectively. The anomalous dispersion signal was judged to be within the range that can provide useful phase information (Micossi et al., 2002 ?). Phases were determined experimentally by single-wavelength anomalous dispersion (SAD) methods using the SeMet derivative. Data to 2.3?? resolution were integrated using XDS (Kabsch, 2010 ?) and then processed with POINTLESS and SCALA (Evans, 2006 ?; Evans & Murshudov, 2013 ?). Initial phases were generated based on four selenium positions using AutoSol in PHENIX (Adams et al., 2010 ?). The resulting electron-density map (figure of merit 0.43) was of excellent quality and allowed the first model of 89 residues to be built.