Linked Life Data

20557091

Source:http://linkedlifedata.com/resource/pubmed/id/20557091

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
2010-7-8
pubmed:abstractText
One electron oxidation of methionine in peptides is highly dependent on the local structure. The sulfur-centered radical cation can complex with oxygen, nitrogen, or other sulfur atoms from a neighboring residue or from the peptidic bond, forming an intramolecular S therefore X two-center three-electron bond (X = S, N, O). This stabilization was investigated computationally in the radical cations of three peptides, methionine glycine (Met Gly) and its reverse sequence Gly Met, and Met Met. Geometry optimizations were done at the BH&HLYP/6-31G(d) level of theory and the effect of solvation was taken into account using a continuum model (CPCM). Up to seven stable conformations were considered for each peptide, with formation of 5-10 member cycles involving nitrogen from the peptidic bond or from the amine, oxygen from the peptidic bond or from the carboxylate group, or sulfur from the other residue for Met Met. The absorption wavelengths corresponding to the sigma --> sigma* transition calculated for each complex at the TD-BH&HLYP/6-311+G(d,p)//BH&HLYP/6-31G(d) level of theory vary from the near-UV for the S therefore O bonds to the green visible for the S therefore S bonds. For X = N, they increase with the SN distance as expected for a 2c-3e bond, whereas for X = O they slightly decrease. Characterization of these 2c-3e bonds as a function of the sequence, using the ELF and the AIM topological analyses, shows the different natures of the S therefore X bonds, which is purely 2c-3e for X = S, mainly 2c-3e with a part of electrostatic interaction for X = N and mainly electrostatic for X = O.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1520-5215
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
114
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7359-68
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Structural and topological studies of methionine radical cations in dipeptides: electron sharing in two-center three-electron bonds.
pubmed:affiliation
Université Pierre et Marie Curie, UMR 7616, Laboratoire de Chimie Théorique, F-75005 Paris, France. fourre@lct.jussieu.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't