Please use this identifier to cite or link to this item:
https://hdl.handle.net/10316/17922
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Kaczor, A. | - |
dc.contributor.author | Reva, I. D. | - |
dc.contributor.author | Proniewicz, L. M. | - |
dc.contributor.author | Fausto, R. | - |
dc.date.accessioned | 2011-12-14T16:25:24Z | - |
dc.date.available | 2011-12-14T16:25:24Z | - |
dc.date.issued | 2007-03-24 | - |
dc.identifier.uri | https://hdl.handle.net/10316/17922 | - |
dc.description.abstract | An extensive analysis of the conformational space of tryptophan (Trp) was performed at the B3LYP/6-311++G(d,p) level and verified by comparison with the infrared spectra of the compound isolated in low-temperature argon and xenon matrixes. Different types of conformers have been unequivocally identified in the matrixes. Type I exhibits the trans arrangement of the carboxylic group and is stabilized by an O−H···N intramolecular H-bond. Types II and III have the carboxylic group in the cis conformation and feature N−H···OC and N−H···O−C hydrogen bonds, respectively. Three individual conformers of type I were identified in the matrixes. Other conformational degrees of freedom are related with the Cα−Cβ−CγC and C1−Cα−Cβ−Cγ angles (χ1 and χ2, respectively). In proteins, these two dihedral angles define the conformations of the amino acid residues. In monomeric Trp, χ1 adopts the “+” (ca. +90°) and “−” (ca. −90°) orientations, while average values of −67.4, 170.5, and 67.6° (“a”, “b”, and “c”, respectively) were found for χ2. Theoretical analysis revealed two important factors in stabilizing the structures of the Trp conformers: the H-bond type and electrostatic interactions. Classified by the H-bond type, the most stable are forms I, followed by II and III. Out of possible combinations of the χ1 and χ2 dihedral angles, “a+”, “b+”, and “c−” were theoretically found more stable than their “a−”, “b−”, and “c+” counterparts. Thus, the stabilizing effect of interactions involving the pyrrole ring (which are possible in Ia+, Ib+, and Ic− conformers) is considerably higher compared to those in which the phenyl ring is engaged (existing in the Ia−, Ib−, and Ic+ forms). | por |
dc.language.iso | eng | por |
dc.publisher | American Chemical Society | por |
dc.rights | openAccess | por |
dc.title | Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers | por |
dc.type | article | por |
degois.publication.firstPage | 2957 | por |
degois.publication.lastPage | 2965 | por |
degois.publication.title | J. Phys. Chem. A | por |
dc.peerreviewed | Yes | por |
dc.identifier.doi | 10.1021/jp070097c | - |
degois.publication.volume | 111 | por |
uc.controloAutoridade | Sim | - |
item.fulltext | Com Texto completo | - |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.grantfulltext | open | - |
item.languageiso639-1 | en | - |
item.openairetype | article | - |
item.cerifentitytype | Publications | - |
crisitem.author.researchunit | CQC - Coimbra Chemistry Centre | - |
crisitem.author.researchunit | CQC - Coimbra Chemistry Centre | - |
crisitem.author.parentresearchunit | Faculty of Sciences and Technology | - |
crisitem.author.parentresearchunit | Faculty of Sciences and Technology | - |
crisitem.author.orcid | 0000-0001-5983-7743 | - |
crisitem.author.orcid | 0000-0002-8264-6854 | - |
Appears in Collections: | FCTUC Química - Artigos em Revistas Internacionais |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
J.Physical Chemistry A, 111 (2007) 2957.pdf | 279.1 kB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.