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61.
A. N. Veselkov L. N. Dymant P. A. Bolotin S. F. Baranovskii D. Shipp D. Davies 《Journal of Structural Chemistry》1996,37(1):65-75
Complexation of the ethidium bromide (3,8-diamino-6-phenyl-5-ethylphenanthridine) dye with self-complementary deoxytetraribonucleoside
triphosphate 5′-d(CpGpCpG) in a water-salt solution is studied by one- and two-dimensional1H NMR spectroscopy (500 MHz). Two-dimensional PMR spectroscopy (2D-COSY and 2D-NOESY) is used for the full assignment of proton
signals of the molecules in the solution and for the qualitative analysis of the interaction between ethidium bromide and
the tetranucleotide. The concentration dependences of the proton chemical shifts of the molecules at a fixed temperature (T=308
K) are measured. Different schemes of the formation of the dye complexes with the tetranucleotide, taking into account various
molecular associations in the solution are considered. The equilibrium constants of the reactions and the limiting chemical
shifts of ethidium bromide protons in the complexes are determined. The relative contents of different complexes in the solution
are analyzed, and the dynamic equilibrium is studied as a function of the dye-tetranucleotide ratio in the solution. The data
obtained suggest that ethidium bromide (like the acridine dye proflavine) is intercalated predominantly into the pyrimidine-purine
sections (CG sites) of the tetranucleotide duplex. However, ethidium bromide is intercalated on the side of the narrow slot
of the duplex, while proflavine intercalation occurs through the broad slot of the double helix. The most likely structures
of the 1∶2 and 2∶2 dye-tetranucleotide complexes in the solution are constructed using the calculated values of the induced
chemical shifts of ethidium bromide protons and 2D NOESY spectroscopy data.
Sevastopol State Technical University. Berkbeck College, London University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 1, pp. 75–87, January–February, 1996.
Translated by I. Izvekova 相似文献
62.
Jasminka Mizdrak Peter G. Hains Danuta Kalinowski Michael J. Davies Joanne F. Jamie 《Tetrahedron》2007,63(23):4990-4999
4-(2-Aminophenyl)-4-oxobutanoic acid, 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid and glutathionyl-kynurenine have been identified as novel metabolites in normal and cataractous human lenses following total synthesis and comparison with authentic human lens samples. Their structures are consistent with those derived from the major human lens UV filters kynurenine and 3-hydroxykynurenine, and it is proposed that these compounds also play a role as UV filters. These metabolites were isolated in pmol/mg levels (dry mass) in lenses. 4-(2-Amino-3-hydroxyphenyl)-4-oxobutanoic acid and glutathionyl-kynurenine were found to be unstable at physiological pH. Other potential metabolites, glutathionyl-3-hydroxykynurenine, kynurenine yellow and 3-hydroxykynurenine yellow, were not detected in either normal or cataractous lenses. 相似文献
63.
Davies RP Linton DJ Schooler P Snaith R Wheatley AE 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(17):3696-3704
The sequential reaction of ZnMe2 with a 2-pyridylamine (HN(2-C5H4N)R, R = Ph: 1; 3,5-Xy (=3,5-xylyl): 2; 2,6-Xy: 3; Bz (=benzyl): 4; Me: 5), tBuLi and thereafter with oxygen affords various lithium zincate species, the solid-state structures of which reveal a diversity of oxo-capture modes. Amine 1 reacts to give both dimeric THF [Li(Me)OZn[N(2-C5H4N)Ph]2] (6), wherein oxygen has inserted into the Zn-C bond of a [MeZn[N(2-C5H4N)-Ph]2] ion, and the trigonal Li2Zn complex, bis(OtBu)-capped (THF x Li)2-[[(mu3-O)tBu]2Zn[N(2-C5H4N)Ph]2] (7). The structural analogue of 6 (8) results from the employment of 2, while the use of more sterically congested 3 yields a pseudo-cubane dimer [(THF x [Li(tBu)OZn(OtBu)Me]]2] (9) notable for the retention of labile Zn-C(Me). Amines 4 and 5 afford the oxo-encapsulation products [mu4-O)Zn4[(2-C5H4N)-NBz]6] (10b), and [tBu(mu3-O)-Li3(mu6-O)Zn3[(2-C5H4N)NMe]6] (11), respectively, with concomitant oxo-insertion into a Li-C interaction resulting in capping of the fac-isomeric (mu6-O)M3M'3 distorted octahedral core of the latter complex by a tert-butoxide group. 相似文献
64.
A method based on dialysis in the presence of histidine, and subsequent copper adsorption and preconcentration using Chelex-100 resin, has been developed for selective extraction of exchangeable copper from blood plasma. The method was verified by comparative analysis using two different instrumental techniques, ICP–MS and AAS. The results obtained were in excellent agreement. Accurate quantification of the exchangeable copper and the firmly bound copper was achieved. The method was further validated by analysis of a lyophilised human serum certified reference material. 相似文献
65.
E. B. Davies 《Communications in Mathematical Physics》1980,71(3):277-288
By carrying out a general analysis of properties of the wave operators for the non-unitary scattering theory which arises in connection with the use of complex optical potentials in nuclear scattering and elsewhere, we clarify some puzzling differences between two recent approaches to this subject. 相似文献
66.
J.C. Hardy G.C. Ball W.G. Davies J.S. Forster H. Schmeing E.T.H. Clifford 《Nuclear Physics A》1981,357(2):356-364
The Q-value for the 129Xe(3He, d)130Cs reaction is measured to be +5 ± 20 keV. By combining this result with the known neutron separation energy of 130Xe, we derive the total decay energy of 130Cs130Xe to beQEC = 2974 ± 20 keV. This value agrees well with two previous positron end-point measurements but disagrees with the corresponding value derived from the 1977 atomic mass evaluation. This has significance in testing the accuracy of the calculated ratio for 130Cs decay. The mass excess of 130Cs is derived to be ?86908 ± 14 keV. An excited state in 130Cs. was also identified at 121 ± 15 keV with J < 3 and positive parity. The Q-value for 136Xe(3He, d)137Cs was measured to be 1918 ± 12 keV. 相似文献
67.
Bunnage ME Davies SG Roberts PM Smith AD Withey JM 《Organic & biomolecular chemistry》2004,2(19):2763-2776
The diastereoselective conjugate addition of lithium (S)-N-benzyl-N-[small alpha]-methylbenzylamide has been successfully applied to the first asymmetric syntheses of cis-(3S,4R)- and trans-(3R,4R)-4-aminotetrahydrofuran-3-carboxylic acids (26% and 25% overall yield respectively, >98% d.e. and >97% e.e. in each case). Furthermore, the most efficient asymmetric synthesis to date of cis-(3R,4R)- and trans-(3R,4S)-4-aminopyrrolidine carboxylic acids is delineated: for cis-(3R,4R), four steps, >98% d.e., 52% overall yield; for trans-(3R,4S), five steps, >98% d.e., 50% overall yield. 相似文献
68.
Varrot A Tarling CA Macdonald JM Stick RV Zechel DL Withers SG Davies GJ 《Journal of the American Chemical Society》2003,125(25):7496-7497
Glycosidases are some of the most ubiquitous enzyme in nature. Their biological significance, coupled to their enormous catalytic prowess derived from tight binding of the transition state, is reflected in their importance as therapeutic targets. Many glycosidase inhibitors are known. Imino sugars are often potent inhibitors, yet many facets of their mode of action, such as their degree, if any, of transition-state "mimicry" and their protonation state when bound to the target glycosidase remain unclear. Atomic resolution analysis of the endoglucanase, Cel5A, in complex with a cellobio-derived isofagomine in conjunction with the pH dependence of Ki and kcat/KM reveals that this compound binds as a protonated sugar. Surprisingly, both the enzymatic nucleophile and the acid/base are unprotonated in the complex. 相似文献
69.
FTIR-RAIRS and ATR techniques are shown to provide a powerful means of investigating the molecular behaviour responsible for the pyroelectric properties of organic monolayer assemblies on silicon and aluminised glass. Spectral changes, associated with either proton transfer or head group rearrangement, are well correlated with the level of pyroelectric response for two different devices. The technique promises to be extremely important for the elucidation of the microscopic properties of molecular electronic devices. 相似文献
70.
A. Abel Lozano M. Dolores Santana Gabriel García J. Elaine Barclay Sin C. Davies David J. Evans 《无机化学与普通化学杂志》2005,631(11):2062-2066
A series of heteronuclear nickel‐iron complexes [Fe2(CO)6(μ‐SH)(μ3‐S){NiCl(PPh3)2}] ( 1 ), [Fe2(CO)6(μ‐SH)(μ3‐S){NiCl(dppe)}] ( 2 ), [Fe2(CO)6(μ3‐S)2{Ni(PPh3)2}] ( 3 ), [Fe2(CO)6(μ3‐S)2{Ni(dppe)}] ( 4 ) and [Fe2(CO)6(μ‐SPh)(μ3‐S){NiCl(dppe)}] ( 5 ) have been prepared. The structure of 4 has been determined by X‐ray crystallography. The central metal‐sulfur core of 4 has a trigonal bipyramidal shape with a NiFe2 base plane with two axial sulfur atoms. Each iron atom is 5‐coordinate forming a distorted square pyramid; the nickel is square planar coordinated by two sulfur atoms and two phosphorus atoms. 相似文献