Exploratory conformational analysis of N-acetyl-L-Tryptophan-N-methylamide. An ab initio study

Ceci, María L.; Verrilli, María A. Lopez; Vallcaneras, Sandra; Bombasaro, J.A.; Rodrı́guez, Ana; Penke, Botond; Enriz, Ricardo D.

doi:10.1016/s0166-1280(03)00261-6

Cited by 10 publications

(5 citation statements)

References 54 publications

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“…Furthermore the N-acetyl and N-methylamide derivatives of homocysteine [15,16] and selenocysteine [17] and of the normal amino acids tryptophane [18,19] histidine [20], methionine [16], isoleucine [21][22][23]23], aspartic acid [24][25][26][27] and glutamine [28] have been theoretically investigated. A further theoretical study combined with FT-IR and Raman measurements on KBr pellets has been performed on N-acetyl-L-alanine [29], N-acetyl-L-aspartic and glutamic acid [30].…”

Section: Introductionmentioning

confidence: 99%

A theoretical and matrix-isolation FT-IR investigation of the conformational landscape of N-acetylcysteine

Boeckx

Ramaekers

Maes

2010

Journal of Molecular Spectroscopy

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Section: Introductionmentioning

confidence: 99%

A theoretical and matrix-isolation FT-IR investigation of the conformational landscape of N-acetylcysteine

Boeckx

Ramaekers

Maes

2010

Journal of Molecular Spectroscopy

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“…In N-acetyl-L-cysteine-N-methylamide, as in all previous cases of L-amino acids studied, [35][36][37][38] R LEFT , D , C 7 ax , and R′ conformers are not preferred because of their relative high-energy values.…”

Section: Locating the Ts Structures At The Pehsmentioning

confidence: 68%

An Exhaustive Conformational Analysis ofN-Acetyl-l-cysteine-N-methylamide. Identification of the Complete Set of Interconversion Pathways on the ab Initio and DFT Potential Energy Hypersurface

Baldoni

et al. 2005

J. Phys. Chem. A

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The full conformational space of N-acetyl-l-cysteine-N-methylamide was explored by ab initio (RHF/ 6-31G(d)) and DFT (B3LYP/6-31G(d)) computations. Multidimensional conformational analysis predicts 81 structures in N-acetyl-l-cysteine-N-methylamide, but only 47 relaxed structures were previously determined at the RHF/3-21G level of theory. These structures were now optimized using RHF/6-31G(d) and B3LYP/6-31G(d) approaches. Seven conformational migrations were observed when recalculated at higher level of theory. Besides these major changes, only smaller conformational shifts were operative for the remaining stationary points. The exploration of the whole conformational space of N-acetyl-l-cysteine-N-methylamide, including the transition-state structures allowing the conformational interconversion among the low-energy forms, was analyzed in this study. Our results offer new insights into the influence of polar side chains on the conformational preferences of peptide structures.

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“…In general, these observations are typical for most amino acids that have been already studied at ab initio level. The current database, which may provide the basis for comparison, includes the following N- and C-protected amino acids containing a trans peptide bond: glycine, , alanine, , valine, phenylalanine, serine, asparagine, aspartic acid, glutamic acid, isoleucine, and cysteine. , Preliminary studies have been published on proline, tryptophan, and Sec . The “typical conformational behavior” of I might be attributed, at least in part, to side chain/backbone interactions that occur in this molecule.…”

Section: Resultsmentioning

confidence: 99%

“…Also R L (g + , g + ) conformation has only 0.59 kcal/mol above the global minima, and it is the second lowest energy form. In addition, we found that N-acetyl-L-isoleucine-N-methylamide 15 and N-acetyl-L-tryptophan-Nmethylamide 16 possess R L conformations in their respective PEHSs. However for these amino acids, R L forms were not the preferred ones.…”

Section: Introductionmentioning

confidence: 83%

Exploration of the Full Conformational Space ofN-Acetyl-l-glutamine-N-methylamide. An ab Initio and Density Functional Theory Study

et al. 2003

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The full conformational space of N-acetyl-l-glutamine-N-methylamide was explored by ab initio (RHF/3-21G and RHF/6-31G(d)) and DFT (B3LYP/6-31G(d)) computations. On the Ramachandran hypersurface of four independent variables, E = E(φ,ψ,χ1,χ2), 59 conformers were located instead of the expected 34 = 81 stable structures. The relative stabilities of the various conformers were analyzed in terms of side chain/backbone interactions covering different hydrogen bonding types by using the theory of atoms in molecules (AIM) and molecular electrostatic potentials (MEPs). The theoretical results were compared with some experimental data (NMR and X-ray).

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Exploratory conformational analysis of N-acetyl-L-Tryptophan-N-methylamide. An ab initio study

Cited by 10 publications

References 54 publications

A theoretical and matrix-isolation FT-IR investigation of the conformational landscape of N-acetylcysteine

A theoretical and matrix-isolation FT-IR investigation of the conformational landscape of N-acetylcysteine

An Exhaustive Conformational Analysis ofN-Acetyl-l-cysteine-N-methylamide. Identification of the Complete Set of Interconversion Pathways on the ab Initio and DFT Potential Energy Hypersurface

Exploration of the Full Conformational Space ofN-Acetyl-l-glutamine-N-methylamide. An ab Initio and Density Functional Theory Study

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