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Determination of the molecular conformation of beta-D-O2,2'-cyclouridine in aqueous solution by proton magnetic resonance spectroscopy 总被引:3,自引:0,他引:3
The solution conformation of β-D -O2,2′-cyclouridine has been determined at 27 and 88°C in D2O by proton magnetic resonance spectroscopy. The conformation is described in terms of a fixed syn-like sugar-base torsional angle, a type S furanose ring conformation (similar to 2′-endo), and a temperature-dependent exocyclic C(4)′–C(5′) rotamer population containing approximately 50% of the gauche-gauche form at 27°C. β-D -O2,2′-Cyclouridine 5′-phosphate likewise possesses a type S furanose ring conformation. 相似文献
34.
Maurice Cross 《BMJ (Clinical research ed.)》1969,4(5686):808-809
35.
An Alcaligenes species, which was isolated from soil, can utilize abietic acid as its sole carbon source. During growth, the bacterium transforms abietic acid into 5alpha-hydroxyabietic acid (I, R=OH), a product considered to be 7beta-hydroxy-13-isopropyl-8xi-podocarp-13-en-15-oic acid (II, R=H) and a compound, C(20)H(28)O(3), which is believed to be an epoxy-gamma-lactone. 相似文献
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37.
I. G. Anderson G. A. D. Haslewood A. D. Cross L. T?kés 《The Biochemical journal》1967,104(3):1061-1063
1. Preliminary spectroscopic examination of a second component of hagfish bile salts suggested that it might be 3β,7α,26(27)-trihydroxy-5α-cholestane. 2. Impure reduction products of the 3β,26(27)-dihydroxycholestane-7,16-dione previously made from myxinol disulphate appeared also to have the 5α-configuration. 3. Infrared, nuclear-magnetic-resonance and mass-spectrographic as well as optical-rotatory-dispersion measurements on 3β,26(27)-dihydroxycholestane-7,16-dione showed that it was a 5α-compound. 4. Myxinol is thus 3β,7α,16α,26(27)-tetrahydroxy-5α-cholestane; new nuclear-magnetic-resonance measurements on myxinol tetra-acetate at higher resolution confirm this structure. 相似文献
38.
ADP-induced inhibition of mitochondrial F1-ATPase has been studied. It is shown that in the presence of magnesium and the absence of light, the photoaffinity ADP analog, 2-azido-ADP, induces a reversible inhibition of native F1 that is indistinguishable from that obtained with ADP. Photolysis of the inactive complex results in the predominant labeling of a catalytic-site peptide identified previously (Cross et al., 1987, Proc. Natl. Acad. Sci. USA 84, 5715-5719). Dissociation of the inactive complex formed between F1 and ADP is biphasic with a rapid azide-insensitive phase followed by a slow azide-sensitive phase (k approximately 3 x 10(-3) s-1). It is also shown that incubation of the ADP-inhibited enzyme with EDTA or phosphate does not result in release or migration of ADP from the catalytic site. However, it does convert the complex to a form that reactivates in the presence of 100 microM ATP at a rate too rapid to observe using manual mixing. 相似文献
39.
Four polymorphic microsatellites in turbot Scophthalmus maximus 总被引:2,自引:0,他引:2
40.
We report a PvuII polymorphism near exon 2 of the dystrophin gene with a heterozygosity frequency of 0.5. 相似文献