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Search query: substrate channeling
20 articles match your search "substrate channeling"Results 1 to 10, sorted by relevance:
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Crystallographic fragment-binding studies of the Mycobacterium tuberculosis trifunctional enzyme have resulted in 121 binding events of 16 out of 226 investigated fragments, suggesting functional sites with respect to substrate binding and substrate channeling.
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Soft X-ray synchrotron radiation transmitted through microchannel plates is studied experimentally.
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Lift-off protocols for thin films of semiconductor and dielectric materials are presented, allowing the structural properties of condensed matter to be studied with EXAFS with improved accuracy.
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A method for obtaining self-standing bent monocrystals is proposed. The crystal curvature was interpreted and parametrized, while the crystallographic quality was verified using hard X-ray diffraction at the DIGRA facility (Institut Laue–Langevin, Grenoble, France).
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Proline utilization A (PutA) is a high-hanging fruit of X-ray crystallography. PutA is a membrane-associated bifunctional flavoenzyme that catalyzes the 4-electron oxidation of proline to glutamate by the sequential activities of proline dehydrogenase and aldehyde dehydrogenase domains. PutAs are challenging crystallography targets because of their long polypeptide chain length (1000-1300 residues) and multidomain architecture. In this talk, I will present new crystal structures and SAXS analysis of two PutAs. Seven high resolution crystal structures of a 1004-residue minimalist PutA were determined using Hg SIRAS phasing, and the oligomeric state and quaternary structure were determined with SAXS [1]. The structures reveal an elaborate and dynamic tunnel system featuring a 75-Å long tunnel that links the two active sites. Also, a novel mechanism-based inactivation strategy allowed the trapping of the elusive PutA-quinone complex in the crystalline state. These structures provide insight into the mechanism of substrate channeling and how the enzyme changes conformation during the catalytic cycle. I will conclude by describing the first structure of a new type of PutA that contains an additional C-terminal domain of unknown function (CTDUF) that is not present in the smaller minimalist enzyme [2]. This larger PutA reveals an unexpectedly different structural solution to the problem of sequestering the reaction intermediate.
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The crystal structure of the oxidized form of a human mitochondrial branched-chain aminotransferase (hBCATm) mutant was determined. The structural analysis supports the concept that a complex regulation mechanism is involved in hBCATm activity, which depends on the key residue Cys315.
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The crystal structures of pyridoxine 5'-phosphate oxidase give an insight into the mechanistic pathway of the enzyme.
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The elastic strain state in a 25 nm (In,Ga)As epitaxic film deposited on a (001) GaAs substrate includes a Poisson expansion perpendicular to the interface. This creates a tetragonally distorted lattice in the film which shifts high-order Laue-zone (HOLZ) lines in electron channeling patterns (ECP) from the film compared to ECP's from pure GaAs. The line shifts are predictable, thereby allowing measurement of elastic strains parallel and perpendicular to the film/ substrate interface independently. The technique appears to have an accuracy close to 0.2%.
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Deposition of a thick film of carbon fibers proved to be an effective method to bend two 5 mm-thick Si monocrystals. High diffraction efficiency was recorded with a 150 keV X-ray beam.
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This feature article reviews the control and understanding of nanoparticle shape from their crystallography and growth. Particular emphasis is placed on systems relevant for plasmonics and catalysis.