High Resolution X-Ray Studies

Structural information about cytochrome oxidase is very limited beyond the level of primary structure as it has proved impossible to grow crystals of sufficiently high quality for high resolution X-ray studies. Cytochrome oxidase is a transmembrane protein which is inserted asymmetrically through the membrane. The overall shape is like a Y, with the stalk extending about 50 A above the membrane plane on the... 

Because of the ease with which molecular mechanics calculations may be obtained, there was early recognition that inclusion of solvation effects, particularly for biological molecules associated with water, was essential to describe experimentally observed structures and phenomena [32]. The solvent, usually an aqueous phase, has a fundamental influence on the structure, thermodynamics, and dynamics of proteins at both a global and local level [3/]. Inclusion of solvent effects in a simulation of bovine pancreatic trypsin inhibitor produced a time-averaged structure much more like that observed in high-resolution X-ray studies with smaller atomic amplitudes of vibration and a fewer number of incorrect hydrogen bonds [33], High-resolution proton NMR studies of protein hydration in aqueous... 

Kavanaugh JS, Rogers PH, Case DA, Arnone A. High resolution x-ray study of deoxyhemoglobin Rothschild 37b Trp to Arg a mutation that creates an intersubunit chloride-binding site. Biochemistry 1992 31 4111-4121. 

Petrache HI, Gouliaev N, Tristam-Nagle S, Zhang R, Suter RM, Nagle IF. Interbilayer interactions high resolution X-ray study. Phys. Rev. E 1998 57 7014-7024. 

High resolution X-ray studies have been reported on the columnar phases of a few compounds. The measurements were made on very well oriented monodomain samples obtained by preparing freely suspended liquid crystal strands, typically about 200 /mi in diameter and 1.5-2 mm... 

In AB -type structures, there are two types of atoms, ions, or molecules. The larger spheres are usually visualized to form an A-type lattice, and the smaller ones occupy some fraction of the holes (cubic, octahedral, or tetrahedral) in that lattice. Which holes are occupied is predicted by the radius ratio of the two spheres. For ionic crystals, the radius ratio is usually calculated as the radius of the cation over that of the anion. Ionic radii are derived from high-resolution X-ray studies. 

Extensive high resolution X-ray studies of the N-SmA transition in a range of... 

Note that within the SmAj phase above the SmA phase, the diffuse peak at Qq 27t//o on the meridian splits into a pair of diffuse peaks on either side of the meridian, indicating the formation of small domains with a SmA-like transverse modulation, as the SmA phase is approached. A high resolution X-ray study of the N-SmA)-SmA transition of DB7NO2 [168, 169] found that two incommensurate smectic fluctuations present in the nematic phase cross over just above the SmAj phase to a region of coexisting incommensurate... 

The first evidence for incommensurate smectic modulations was obtained by Leadbetter and coworkers in the smectic E phase of n-alkyl cyanoterphenyls [181, 182]. Subsequent studies presented evidence for fluid SmAi SmA2,i c and SmAinc soliton phases in binary mixtures [183-185]. However, more recent high resolution X-ray studies have contradicted these latter findings and have found that the apparently incommensurate phases are actually coexistence regions between various smectic phases (e.g. SmAi-bSmA SmA2 + SmAd) [24, 186-189]. These authors have recently claimed to have found a true incommensurate ordered smectic phase in mixtures of TBBA and DB6 [190]. Evidence has also been presented for two soli-ton-type incommensurate SmA phases (one... 

High resolution X-ray studies of DNA decamers are compared to model calculations using JUMNA on simple repetitive sequences. " Helicoidal parameters are calculated with CURVES." ... 

Singh U (2011) Effect of polymer networks on the smectic-C phase of a ferroelectric liquid crystal high-resolution x-ray studies. Phys Rev E 83 061707... 

The crystalline smectics Sb, Se, Sq, Sh, Sj and Sk- These phases were identified as smectics on the basis of microscopic observations. However, recent high resolution X-ray studies have shown that these modifications possess three-dimensional positional order, though with extremely weak interlayer forces. These highly ordered phases cannot therefore be called LCs in the strict definition of the term. 

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