Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers
Autor(a) principal: | |
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Data de Publicação: | 2007 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/17922 https://doi.org/10.1021/jp070097c |
Resumo: | 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). |
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Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing ConformersAn 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).American Chemical Society2007-03-24info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/17922http://hdl.handle.net/10316/17922https://doi.org/10.1021/jp070097cengKaczor, A.Reva, I. D.Proniewicz, L. M.Fausto, R.info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2022-05-25T03:43:56Zoai:estudogeral.uc.pt:10316/17922Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:01:45.221647Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers |
title |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers |
spellingShingle |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers Kaczor, A. |
title_short |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers |
title_full |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers |
title_fullStr |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers |
title_full_unstemmed |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers |
title_sort |
Matrix-Isolated Monomeric Tryptophan: Electrostatic Interactions as Nontrivial Factors Stabilizing Conformers |
author |
Kaczor, A. |
author_facet |
Kaczor, A. Reva, I. D. Proniewicz, L. M. Fausto, R. |
author_role |
author |
author2 |
Reva, I. D. Proniewicz, L. M. Fausto, R. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Kaczor, A. Reva, I. D. Proniewicz, L. M. Fausto, R. |
description |
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). |
publishDate |
2007 |
dc.date.none.fl_str_mv |
2007-03-24 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10316/17922 http://hdl.handle.net/10316/17922 https://doi.org/10.1021/jp070097c |
url |
http://hdl.handle.net/10316/17922 https://doi.org/10.1021/jp070097c |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
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1799133907940016128 |