7.6.2.8 analysis of the cobinamide (Cbi)-bound BtuF crystal structure model, PDB ID 5M29, crystal structures of Cbi-bound BtuF mutants W66F, W66Y and W66L, sitting drop vapor diffusion technique, mixing of 20 mg/ml protein in 10 mM Tris pH 8 and 100 mM NaCl, with precipitant solution containing 1% w/v tryptone, 50 mM HEPES, pH 7.0, and 12% w/v PEG 3350, 1-2 weeks, 20°C, X-ray diffraction structure determination and analysis at 1.5-1.7 A resolution, molecular replacement using the BtuF structure (PDB ID 1N2Z) as search model 752221 7.6.2.8 BtuCD-F complex analyzed at a resolution of 2.6 A, substantial conformational changes observed as compared with previously reported structures of BtuCD and BtuF 690056 7.6.2.8 BtuCD-F complex, and HI470/1 X-ray diffraction structure analysis using PDB-IDs 2NQ2, 1L7V and 2QI9, overview 696776 7.6.2.8 catalytically impaired BtuCD mutant E159Q in complex with BtuF, to 3.5 A resolution. The BtuC subunits adopts a distinct asymmetric conformation. The structure suggests that BtuF does not discriminate between, or impose, asymmetric conformations of BtuCD 719509 7.6.2.8 crystal structure analysis of the crystal structure of the BtuCD-F complex, modelling, overview 697950 7.6.2.8 elucidation of gating mechanism by EPR spectroscopy. The translocation gates of the BtuCDF complex undergo conformational changes in line with a two-state alternating access model. Binding of ATP drives the gates to an inward-facing conformation. Following ATP hydrolysis, the translocation gates restore to an apo-like conformation. In the presence of ATP, an excess of vitamin B12 promotes the reopening of the gates toward the periplasm and the dislodgement of BtuF from the transporter 719987 7.6.2.8 in complex with beta-gamma-imidoadenosine 5'-triphosphate, sitting drop vapor diffusion method, using 20-30% (w/v) PEG 400, 100 mM N-(2-acetamido)-iminodiacetic acid, pH 6.8, 100 mM sodium potassium citrate 734771 7.6.2.8 molecular dynamics simulations to explore the atomic details of the conformational transitions of BtuCD importer. The outward-facing to inward-facing transition is initiated by the conformational movement of nucleotide-binding domains. The subsequent reorientation of the substrate translocation pathway at transmembrane domains begins with the closing of the periplasmic gate, followed by the opening of the cytoplasmic gate in the last stage of the conformational transition due to the extensive hydrophobic interactions at this region, consistent with the functional requirement of unidirectional transport of the substrates. The reverse inward-facing to outward-facing transition exhibits intrinsic diversity of the conformational transition pathways and significant structural asymmetry 720849 7.6.2.8 mutant E159Q/N162C in complex with adenylyl imidodiphosphate, sitting drop vapor diffusion method, using 100 mM ADA buffer, pH 6.9, 1.2 M NaCl, and 14-18% (w/v) PEG 2000 MME 734760 7.6.2.8 purified ECF-CbrT complex in detergent (n-dodecyl-beta-D-maltopyranoside) solution, sitting drop vapour diffusion method, mixing of protein solution containing 50 mM HEPES pH 8, 150 mM NaCl, 1% polyoxyethylene(10)dodecyl ether, with precipitant solution containing 0.2 M KCl, 0.1 M sodium citrate, pH 5.5, 37% v/v pentaerythritol propoxylate, X-ray diffraction structure determination and analysis at 3.4 A resolution, molecular replacement with the structure of the folate transporter, ECF-FolT2, from Lactobacillus delbrueckii as a search model 750412