Vibrational circular dichroism in amino acids and peptides. 8. A chirality rule for methine C*.alpha.-H stretching modes

Nafie, Laurence A.; Oboodi, M. Reza; Freedman, Teresa B.

doi:10.1021/ja00363a044

Cited by 43 publications

(42 citation statements)

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“…la Many chiral molecules containing covalent or intramolecularly hydrogenbonded rings exhibit VCD spectra displaying features biased to either positive or negative VCD intensity.l3? [17][18][19][20][21][22] Su acids, a-hydroxy acids, transition metal complexes, sugars, dipeptides, and polypeptides. Biased VCD features can be understood in terms of the vibrational ring current mechanism, wherein nuclear oscillations adjacent to or within an intramolecular ring generate oscillating electronic current in the ring that occurs at constant electron density.…”

Section: Introductionmentioning

confidence: 99%

Vibrational CD studies of the solution conformation of N‐urethanyl‐L‐amino acid derivatives

1987

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SynopsisThe solution conformations of several N-urethanyl-L-amino acids in 0.2-0.002M chloroform and 0.2M dimethylsulfoxide have been investigated by Using vibrational circular dichroism (VCD), ir absorption, and 13C-nmr spectroscopies. Both the N-carbobenzoxy (N-CBZ) and N-t-butoxycarbonyl derivatives of L-alanine, L-proline, L-valine, and L-phenylalanine, and N-CBZ-serine were studied. The "C-nmr results indicate that the molecules occur predominantly as the cis isomer about the C-N peptide bond at room temperature. The interpretation of the strong VCD couplet in the carbonyl-stretching region using the degenerate coupled oscillator model is consistent with the conformational range of Q = -60" to -90" and 4 = 30" to 9 0 ' for molecules forming acid dimers. Conformations with an intramolecularly hydrogen-bonded C , ring are also present, which give rise to biased VCD features in the NH-, CH-, and C=O-stretching regions that can arise due to vibrationally generated ring currents.

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Section: Introductionmentioning

confidence: 99%

Vibrational CD studies of the solution conformation of N‐urethanyl‐L‐amino acid derivatives

1987

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“…the experimental vCd studies comparing results obtained for several amino acids started in 1983 by the observation that the C*h vCd band of L-amino acids in aqueous solution exhibits a strong positive bias [147]. In that study, all natural α-amino acids (except aspartic and glutamic acids, tyrosine, and tryptophan, but additionally allo-threonine, 4-hydroxy proline, and allo-4-hydroxy proline) and penicillamine were registered.…”

Section: Vibrational Chiroptical Studies On Common Amino Acid Charactmentioning

confidence: 95%

“…however, in 1977, the first reliable registration of the vCd spectra of L-and d-alanine-d 3 in heavy water in the Ch stretching vibrations region (3100-2850 cm −1 ) was a very challenging task [167]. Since then, alanine vCd spectra have been repetitively measured [147][148][149][168][169][170][171][172][173][174][175][176] and calculated [144,171,172,175,[177][178][179][180][181][182][183].…”

Section: Vibrational Chiroptical Studies On Common Amino Acid Charactmentioning

confidence: 99%

“…VCD spectra: Experiment and Calculations L-proline is a relatively small, rigid and water-soluble amino acid which, probably, is the main reason why the number of vCd and RoA studies dedicated to it is greater than for the other natural amino acids except for L-alanine. the vCd C*h stretching and bending vibrations bands of L-proline (along with 4-hydroxy and allo-4-hydroxy proline) were measured in water in the 1980s, revealing a pattern characteristic of all L-amino acids [147][148][149]. therefore, it is surprising that the first systematic study of the vCd spectra of L-proline in water was a computational study by Cappelli et al in 2005 [201].…”

Section: Roa Spectra: Experiments and Calculationsmentioning

confidence: 99%

“…No simple correlation between the ring conformation and the RoA intensity of those vibrations was found. [147][148][149][150]. Since then, the vibrational optical activity of L-cysteine has been studied only sporadically.…”

Section: L-prolinementioning

confidence: 99%

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α-Amino Acids In Water: A Review Of VCD And ROA Spectra

Dobrowolski

Lipiński

Rode

et al. 2013

Challenges and Advances in Computational Chemistry and Physics

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An up-to-date perspective on the capability of vibrational Circular dichroism (vCd) and Raman optical Activity (RoA) spectroscopy of the 20 encoded α-amino acids to solve the structural problems appearing in water is provided in this review. VCD and ROA spectroscopy of the α-amino acid molecules reviewed in this chapter refer only to free and single amino acids in water at various ph levels. to well understand the implications of such studies for biology and medicine, we devote one subchapter to the role of free amino acids in an organism's metabolism and physiology. A variety of side chains that modify the α-amino acids character from acidic to basic and from hydrophilic to hydrophobic makes the possible dissociation equilibria in water very complex and dependent on several factors. therefore, information on dissociation constants, isoelectric points, and hydrophobicity parameters of α-amino acids is summarised in the next subchapter. The conformational variety, complexity of interactions, and entanglement of equilibria makes considering the influence of these factors on vCd and RoA spectra with quantum chemical analysis absolutely necessary. the elements of the theory of chiroptical vibrational spectra and methods enabling solvent simulations are provided in the subsequent subchapter. We report on experimental methods, techniques and tricks for measuring and simulating the vCd and RoA spectra in water at different ph levels. the review is concluded by listing the not-yet-measured amino acids, a presentation of the main challenges for computational methods, and suggestions for the most promising experimental techniques that may be used in future studies. Keywords

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The a Priori Calculation of Vibrational Circular Dichroism Intensities

Yang

Rauk

1996

Reviews in Computational Chemistry

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Vibrational circular dichroism in amino acids and peptides. 8. A chirality rule for methine C*.alpha.-H stretching modes

Cited by 43 publications

References 0 publications

Vibrational CD studies of the solution conformation of N‐urethanyl‐L‐amino acid derivatives

Vibrational CD studies of the solution conformation of N‐urethanyl‐L‐amino acid derivatives

α-Amino Acids In Water: A Review Of VCD And ROA Spectra

The a Priori Calculation of Vibrational Circular Dichroism Intensities

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