Influence of the side chain in the structure and fragmentation of amino acids radical cations

Adrià Gil, Silvia Simon, Luis Rodríguez-Santiago, Juan Bertrán, Mariona Sodupe

Producció científica: Contribució a una revistaArticleRecercaAvaluat per experts

43 Cites (Scopus)


The conformational properties of ionized amino acids (Gly, Ala, Ser, Cys, Asp, Gln, Phe, Tyr, and His) have been theoretically analyzed using the hybrid B3LYP and the hybridmeta MPWB1K functional as well as with the post-Hartree Fock CCSD(T) level of theory. As a general trend, ionization is mainly localized at the -NH2 group, which becomes more planar and acidic, the intramolecular hydrogen bond in which -NH2 acts as proton donor being strengthened upon ionization. For this reason, the so-called conformer IV(+) becomes the most stable for nonaromatic amino acid radical cations. Aromatic amino acids do not follow this trend because ionization takes place mainly at the side chain. For these amino acids for which ionization of the side chain prevails over the -NH2 group, structures lll(+) and ll(+) become competitive. The Cα-X fragmentations of the ionized systems have also been studied. Among the different decompositions considered, the one that leads to the loss of COOH• is the most favorable one. Nevertheless, for aromatic amino acids fragmentations leading to R• or R+ start being competitive. In fact, for His and Tyr, results indicate that the fragmentation leading to R+ is the most favorable process. © 2007 American Chemical Society.
Idioma originalEnglish
Pàgines (de-a)2210-2220
RevistaJournal of Chemical Theory and Computation
Estat de la publicacióPublicada - 1 de nov. 2007


Navegar pels temes de recerca de 'Influence of the side chain in the structure and fragmentation of amino acids radical cations'. Junts formen un fingerprint únic.

Com citar-ho