Molecular and crystal structure and quantum-chemical calculation of the molecule of N?-acetyl-aza-??-homo-l-valine dimethylamide

Mishnev, A. F.; Bleidelis, J.; Ancans, J. E.; Cipens, G. I.

doi:10.1007/bf00790767

Cited by 2 publications

(6 citation statements)

References 3 publications

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“…On the other hand, the structures of two related molecules also have been also reported. 18,19 Such compounds only differ from 13 in the end alkyl groups. Thus, the (CH 3 ) 2 N-CO 18 and (CH 3 ) 3 C-CO 19 moieties replaced the end acetyl groups.…”

Section: Resultsmentioning

confidence: 99%

“…18,19 Such compounds only differ from 13 in the end alkyl groups. Thus, the (CH 3 ) 2 N-CO 18 and (CH 3 ) 3 C-CO 19 moieties replaced the end acetyl groups. However, the influence of these modifications in the backbone conformation is quite small, i.e., φ 1 , φ 2 ) 105°, -124°1 8 and φ 1 , φ 2 ) 101°, -99°, 19 respectively.…”

Section: Resultsmentioning

confidence: 99%

“…For 13 the comparison with experiment is more difficult because the final agreement factor R for the three compounds containing the gem-diamino residue was too large. [17][18][19] 6 and 7, providing standard deviations of 0.012 Å and 0.7° (12) and 0.011 Å and 0.8°(13).…”

Section: Resultsmentioning

confidence: 99%

“…This work presents an ab initio quantum mechanics study on the partially modified retro-inverso compounds derived from valine dipeptide ( 12 and 13 ). Valine was selected as parent residue by two reasons: (1) It presents a higher percentage of occurrence in proteins than other residues; and (2) the X-ray-determined structures of dipeptides containing the corresponding malonyl and gem -diamino residues are available in the literature. − The minimum energy conformations located for 12 and 13 have been compared with those reported for other partially modified retro-inverso dipeptides. Results have allowed us to understand how the side chain affects the conformational preferences of malonyl and gem -diamino residues.…”

Section: Introductionmentioning

confidence: 99%

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A Computational Study of Partially Modified Retro-Inverso Valine Dipeptides: Effect of the Side Chain on the Conformational Preferences of Malonyl and gem-Diamino Residues

Alemán

2001

J. Phys. Chem. B

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A high-level study of the partially modified retro-inverso compounds derived from valine dipeptide, i.e., CH3NHCOCHRCONHCH3 and CH3CONHCHRNHCOCH3 where R = −CH(CH3)2, is presented. Minimum energy conformations were obtained at the HF/6-31G(d) and MP2/6-31G(d) levels from a systematic conformational analysis. The effects of electron correlation and basis set on relative energies were investigated by performing single point calculations at the HF/6-311G(d,p) and MP2/6-311G(d,p) levels on both HF/6-31G(d) and MP2/6-31G(d) geometries. Furthermore, the influence of polar solvents, i.e., water and methanol, on the conformational preferences of the two compounds was determined using the polarizable continuum model. A comparison with results previously obtained for other partially modified retro-inverso dipeptides promoted an understanding of how the side chain affects the conformational preferences of the malonyl and gem-diamino residues.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Computational Study of Partially Modified Retro-Inverso Valine Dipeptides: Effect of the Side Chain on the Conformational Preferences of Malonyl and gem-Diamino Residues

Alemán

2001

J. Phys. Chem. B

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“…A relatively small number of crystal structures of retro‐peptides has been reported. Two helical32, 33 and seven extended20, 34–39 conformations have been found in crystal structures containing gem ‐diamino alkyl moieties, while five helical40–43 and three extended42, 44, 45 conformations have been found in crystal structures containing malonyl residues. The local minima, derived from energy calculations, and the backbone torsion angles, determined from x‐ray crystal structures of gem ‐diamino alkyl and malonyl residue containing peptides, have been summarized in a recent review 46…”

Section: Introductionmentioning

confidence: 99%

Extended form of a retro-inverso peptide stabilized by ?-sheet unidirectional H-bonds: Crystallographic and NMR evidence

et al. 2001

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The crystallographic investigation of the retro–inverso peptide Bz–S–gAla–R–mAla–NHPh reveals an extended backbone conformation where the NH groups of the gem‐diamino alkyl moiety and the CO groups of the malonyl residue face side by side. This extended conformation, presenting all carbonyls on opposite sides of the NH groups, is stabilized by interstrand H‐bonds running in a single direction of the parallel β‐sheets that characterize the crystal packing. These sheets differ from the β‐sheets formed by native amino acids only. 1H‐NMR nuclear Overhauser effect spectroscopy (NOESY) experiments suggest that a conformation similar to that found in the crystal also prevails in dimethylsulfoxide solution. Previous potential energy calculations of gem‐diamino alkyl (g) and malonyl (m) Ala residues predicted that extended forms were less stable than the helical ones because of strong electrostatic repulsions between the parallel polar groups. Similar arguments were invoked to give more weight to helical forms of the retro‐peptide units in the proposal of packing models of some nylons in their crystalline polar regions. The present findings show that both g and m Ala residues can experience the extended conformation in the β‐sheet aggregation. The energy increase occurring in one strand, due to the parallel orientation of consecutive peptide dipoles, is more than compensated by favorable cooperative interactions among head‐to‐tail aligned peptide dipoles of facing strands, resulting in the formation of two CO · · · HN H‐bonds per residue. © 2001 John Wiley & Sons, Inc. Biopolymers (Pept Sci) 60: 322–332, 2001

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Molecular and crystal structure and quantum-chemical calculation of the molecule of N?-acetyl-aza-??-homo-l-valine dimethylamide

Cited by 2 publications

References 3 publications

A Computational Study of Partially Modified Retro-Inverso Valine Dipeptides: Effect of the Side Chain on the Conformational Preferences of Malonyl and gem-Diamino Residues

A Computational Study of Partially Modified Retro-Inverso Valine Dipeptides: Effect of the Side Chain on the Conformational Preferences of Malonyl and gem-Diamino Residues

Extended form of a retro-inverso peptide stabilized by ?-sheet unidirectional H-bonds: Crystallographic and NMR evidence

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