Nuclear Magnetic Resonance Studies of Hydrogen Bonding

Eyman, Darrell P.; Drago, Russell S.

doi:10.1021/ja00960a005

Cited by 93 publications

(41 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The chemical shifts of imino protons are highly sensitive to hydrogen-bond length (29) [and probably energy (30) An increase in temperature acts to remove this feature from the imino proton spectra by shifting the more downfield [ (Fig. 2) is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Structural basis for DNA bending.

Nadeau

Crothers

1989

Proc. Natl. Acad. Sci. U.S.A.

144

124

View full text Add to dashboard Cite

We report proton NMR studies on DNA oligonucleotides that contain A tracts of lengths known to produce various degrees of bending. Spectra of duplexes in the series 5'-(GGCA.CGG)-(CCGT.GCC) (n = 3, 4, 5, 7, 9) reveal substantial structural changes within the A.-T. tract as its length is increased. Chemical-shift comparisons show that A tracts with fewer than about seven members do not contain regions of uniform [or poly(dA)-poly(dT)-like] structure. Long

show abstract

Section: Resultsmentioning

confidence: 99%

Structural basis for DNA bending.

Nadeau

Crothers

1989

Proc. Natl. Acad. Sci. U.S.A.

144

124

View full text Add to dashboard Cite

show abstract

“…However, it is not established that other base pair resonances not in helical arms have identical resonance positions. In fact it has been proposed that the NMR shifts in a hydrogen bond are proportional to the enthalpy of the hydrogen bond (10,11).…”

Section: Results and Assignmentsmentioning

confidence: 99%

Assignment of the Hydrogen Bonded Proton Resonances in ( Escherichia coli ) tRNA ^Glu by Sequential Melting

Hilbers¹,

Shulman²

1974

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The 300 resonances of which 20 are assigned to the twenty base pairs predicted by the cloverleaf model (see Fig. 1), based upon the primary sequence determined by Munninger and Chang (4). In the past (5), the accuracy in counting protons has been limited to ±2 protons out of 20 so that it has been possible to exclude contributions from four or five tertiary structure Watson-Crick base pairs predicted by certain models of tRNA (see, for instance, ref. 6). In the present study the melting behavior enables us to resolve 21 separate resonances and one of them is assigned to a tertiary structure base pair. RESULTS AND ASSIGNMENTSFigs. [2][3][4] show the 300 MHz NMR spectra of the (E. coli)-tRNAGlu sample at different temperatures. Fig. 2a presents the spectrum at 250 which is very similar to that reported previously under the same conditions (2). In the previous interpretation of this spectrum we assigned the four lowest

show abstract

“…Phenols possess an acidic hydroxyl group well suited to hydrogen bond formation. It has been well documented (10)(11)(12) that phenols hydrogen bond to dimethylsulfoxide and hence the observed "'Co shifts will be the outcome of a competition between the solvent and the cobalticyanide for the phenolic hydrogen bond. The choice of a range of phenols with both electron withdrawing and electron donating substituents allows a systematic study of this competition.…”

Section: A "Co C H E~~~i C a Lmentioning

confidence: 99%

Second sphere coordination of phenols, anilines, and benzoic acids to the hexacyanocobaltate(III) anion

Eaton¹,

Buist²,

Rogerson³

1983

Can. J. Chem.

View full text Add to dashboard Cite

Can. J. Chem. 61, 1524 (1983. Complexing between the hexacyanocobaltatc(lI1) anion and ten substitutcd phenols, cight substituted anilines, and eight substituted benzoic acids has been studied in dimethyl sulfoxide solutions by mcans of '"Co nmr. For the phenols substantial changes in the chemical shifts and in the linc widths are obscrvcd and are attributed to hydrogen bonding interactions. Effective equilibrium constants and chemical shifts for the hydrogcn bondcd species have been calculated. Thc equilibrium constants vary with the phcnol substituent, being largest for electron withdrawing substituents and smallest for electron donating substituents. The chemical shifts are virtually independent of substituent. The data show that the lifetimes of the hydrogen bonded complexes are long compared to the rotational correlation time. Thc complex with porn-nitrophenol has also been studied by measuring 'H and '.'C spin-lattice relaxation times. These measurements allow the separation of the increase in 59 Co line width due to increase in correlation time and that due to increase in quadrupolc coupling constant. From the I3C measurements a value of the correlation time for the complex of 2.8 1 0~" ' s is obtained together with a '9Co quadrupole coupling constant of 8.34 MHz. The equilibrium constants for complex formation with the anilincs are small and only the products of the equilibrium constant and the chernical shift of thc hydrogen bonded complex can be derived from the experimental data. The bcnzoic acids show evidence of dinicrization in solution and this again prevcnts the calculation of absolute equilibrium constants. The data, however, do indicate that the ability to form hydrogcn bond complexes does not vary dramatically with thc acid strength of the hydrogen donor. With phenols and benzoic acids therc is considerable linc broadening on complex formation but with anilines only a small line broadening is obscrved. This is consistent with very short hydrogen bond lifetimes for the aniline complexes. DONALD R. EATON, RICHARD J . BUIST et CAROL V. ROGERSON. Can. J. Chcm. 61, 1524 (1983. Faisant appel ii la rmn du ' "0, on a CtudiC la complexation de l'anion hcxacyano cobaltate(lll) avec dix phenols substituks, huit anilines substitukes et huit acides bcnzo'iqucs substituCes dans des solutions dc dimCthylsulfoxide. Dans le cas des phknols on observe des changements importants dans Ics dkplacements chimiques et dans la largeur des raies et on les attribue i des interactions de liaison hydrogknc. On a calculC les constantes effectivcs d'kquilibre et les dCplacements chimiques des espkces likes par des liaisons hydrogknes. Les constantes d'dquilibre varient avcc le substituant du phdnol. cette constante est plus ClevCe dans le cas des substituants dlectro-attracteurs ct plus faible dans le cas des substituants Clectro-donneurs. Les dCplacements chimiques sont virtuellement indkpendants du substituant. Les donnCes montrent que les temps de vie des complexes liCs par des liaisons hydrogknes sont longs par rapport...

show abstract

Nuclear Magnetic Resonance Studies of Hydrogen Bonding

Cited by 93 publications

References 0 publications

Structural basis for DNA bending.

Structural basis for DNA bending.

Assignment of the Hydrogen Bonded Proton Resonances in ( Escherichia coli ) tRNA ^Glu by Sequential Melting

Second sphere coordination of phenols, anilines, and benzoic acids to the hexacyanocobaltate(III) anion

Contact Info

Product

Resources

About

Nuclear Magnetic Resonance Studies of Hydrogen Bonding

Cited by 93 publications

References 0 publications

Structural basis for DNA bending.

Structural basis for DNA bending.

Assignment of the Hydrogen Bonded Proton Resonances in ( Escherichia coli ) tRNA Glu by Sequential Melting

Second sphere coordination of phenols, anilines, and benzoic acids to the hexacyanocobaltate(III) anion

Contact Info

Product

Resources

About

Assignment of the Hydrogen Bonded Proton Resonances in ( Escherichia coli ) tRNA ^Glu by Sequential Melting