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KL Britton HF Rogers Y Asano T Dairi Y Kato TJ Stillman DW Rice 《Acta crystallographica. Section D, Biological crystallography》1998,53(4):124-126
The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp. strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse substrate specificites. Crystals of this opine dehydrogenase, obtained in the presence or absence of co-factor and substrates, have been shown to diffract to beyond 1.8 ? resolution. X-ray precession photographs have established that the crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0, c = 45.5 ? and a single subunit in the asymmetric unit. The elucidation of the three-dimensional structure of this enzyme will provide a structural framework for this novel class of dehydrogenases to enable a comparison to be made with other enzyme families and also as the basis for mutagenesis experiments directed towards the production of natural and synthetic opine-type compounds containing two chiral centres. 相似文献
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J. P. Shannon D. W. Blinn G. A. Haden E. P. Benenati K. P. Wilson 《Isotopes in environmental and health studies》2013,49(3):179-191
Abstract Dual stable isotope analysis in the regulated Colorado River through Grand Canyon National Park, USA, revealed a food web that varied spatially through this arid biome. Down-river enrichment of δ13C data was detected across three trophic levels resulting in shifted food webs. Humpack chub δ13C and δ15N values from muscle plugs and fin clips did not differ significantly. Humpback chub and rainbow trout trophic position is positively correlated with standard length indicating an increase in piscivory by larger fishes. Recovery of the aquatic community from impoundment by Glen Canyon Dam and collecting refinements for stable isotope analysis within large rivers are discussed. 相似文献
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Li X Blinn K Fang Y Liu M Mahmoud MA Cheng S Bottomley LA El-Sayed M Liu M 《Physical chemistry chemical physics : PCCP》2012,14(17):5919-5923
SERS provided by sputtered silver was employed to detect trace amounts of chemical species on SOFC electrodes. Considerable enhancement of Raman signal and lowered detection threshold were shown for coked nickel surfaces, CeO(2) coatings, and cathode materials (LSM and LSCF), suggesting a viable approach to probing electrode degradation and surface catalytic mechanism. 相似文献
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In this paper we discuss the recovery of derivatives and thecomputation of rigorous and useful upper bounds for the pointwiseerror in the recovered derivatives, for finite element approximationsof the Laplace equation with Neumann boundary conditions, especiallyat points close to or on a smooth, curved boundary. We analyzethe dipole image technique for the case of curved boundaries,and show how to compute reliable recovered derivatives and errorbounds even in the limiting case of points lying on the curvedboundary. Numerical experiments show reasonably tight errorbounds for points both close to and away from a curved boundary. 相似文献
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The photochemistry of 3 - methyl - 3 - (1' - naphthyl) -1 - butene was investigated. Direct irradiation led to 1,1 dimethyl - 2 - (1' - naphthyl)cyclopropane as a primary photoproduct and 2 - methyl - 4 - (1' - naphthyl) - 1 - butene as -a secoandary product. The quantum yield for the formation of the cyclopropane was 0.037. The corresponding triple reaction was less efficient, with a quantum yield of 0.012, but still afforded the same product. The excited single rearragement rate was determined by single photon counting; this proved to be 1kXXX = 5.9 × 105 sec-1.The total rate of S1 decay was determined as 1.59 × 107 sec-1 with a lifetime of 62.9 nsec.Thus, the lifetime of this rearranging system is quite simiar to that of simple 1-alkylnaphthalenes (Ca 65 nsec); and, the rate of di-π-methane rearrangement is the slowest known. Finally, the rate of radiationless decay of the singlet was found to be almost temperature independent between room temperature and 77 K. 相似文献
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Frank W. Crow Wayne K. Duholke Gary E. Martin Richard F. Smith Thomas J. Thamann Anne M. Cooper John W. Hallberg James R. Blinn Constance G. Chidestere 《Journal of heterocyclic chemistry》1999,36(4):1049-1055
The structure of a novel, thermally-induced degradant of the antibiotic pirlimycin is presented. The degradant was discovered during thermal stress stability testing of pirlimycin. The structure was determined using high resolution mass spectrometry, ms/ms fragmentation, and extensive nmr studies including a combination of homonuclear TOCSY and gradient, inverse-detected 2-D nmr experiments which included GHSQC and GHMBC. All nmr, high resolution ms and ms/ms fragmentation data are consistent with loss of a molecule of HCl during a ring closure involving one of the hydroxyl moieties from the sugar portion of the molecule forming a tetrahydrofurano[3,2-b]perhydropyran ring structure. The X-ray crystal structure is reported for pirlimycin. Using this structure molecular modelling studies are performed which demonstrate the feasibility of the formation of the new structure. 相似文献
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Shannon JP Blinn DW Haden GA Benenati EP Wilson KP 《Isotopes in environmental and health studies》2001,37(3):179-191
Dual stable isotope analysis in the regulated Colorado River through Grand Canyon National Park, USA, revealed a food web that varied spatially through this arid biome. Down-river enrichment of delta13C data was detected across three trophic levels resulting in shifted food webs. Humpack chub delta13C and delta15N values from muscle plugs and fin clips did not differ significantly. Humpback chub and rainbow trout trophic position is positively correlated with standard length indicating an increase in piscivory by larger fishes. Recovery of the aquatic community from impoundment by Glen Canyon Dam and collecting refinements for stable isotope analysis within large rivers are discussed. 相似文献
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