INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS

Ab initio calculations at the MP2/6-31G** level have been carried out on the non-Watson-Crick nucleic acids pairs G<FONT FACE=Symbol>·</FONT>U and U<FONT FACE=Symbol>·</FONT>U to obtain the interaction energies and to see whether the derived values are c...

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Autores principales:	MADARIAGA,SANDRA T, CONTRERAS,J.GUILLERMO, SEGUEL,C.GLORIA
Lenguaje:	English
Publicado:	Sociedad Chilena de Química 2005
Materias:	Ab initio interaction energies G<FONT FACE=Symbol>·</FONT>U <FONT FACE=Symbol>·</FONT>U pairs
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072005000100013
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spelling	oai:scielo:S0717-970720050001000132005-05-27INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRSMADARIAGA,SANDRA TCONTRERAS,J.GUILLERMOSEGUEL,C.GLORIA Ab initio interaction energies G<FONT FACE=Symbol>·</FONT>U <FONT FACE=Symbol>·</FONT>U pairs Ab initio calculations at the MP2/6-31G** level have been carried out on the non-Watson-Crick nucleic acids pairs G<FONT FACE=Symbol>·</FONT>U and U<FONT FACE=Symbol>·</FONT>U to obtain the interaction energies and to see whether the derived values are comparable or not with the canonical G-C, A-T and A-U pairs. Optimized geometries of the pairs show that the structural parameters of the isolated bases differ very little on pairing. The guanine -NH2 group does not participate in the hydrogen bonding formation and possesses a pyramidal structure; its intrinsic nonplanarity plays an important role in the out-of-plane intermolecular interactions. Thus, the G<FONT FACE=Symbol>·</FONT>U pair projects three hydrogen bonding acceptor sites, namely, N7(G), O6(G) and O4(U) to the RNA major groove. The interaction energy (DHºint) calculated for the G<FONT FACE=Symbol>·</FONT>U pair (-13.6 kcal/mol) is comparable to that determined for A-T (-13.0 kcal/mol), but considerable smaller than the experimental value reported for G-C (-21.0 kcal/mol). The U<FONT FACE=Symbol>·</FONT>U pair follows the trend that pairing between pyrimidines bases should have lower interacting energies than purine-pyrimidine pairsinfo:eu-repo/semantics/openAccessSociedad Chilena de QuímicaJournal of the Chilean Chemical Society v.50 n.1 20052005-03-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072005000100013en10.4067/S0717-97072005000100013
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Ab initio interaction energies G<FONT FACE=Symbol>·</FONT>U <FONT FACE=Symbol>·</FONT>U pairs
spellingShingle	Ab initio interaction energies G<FONT FACE=Symbol>·</FONT>U <FONT FACE=Symbol>·</FONT>U pairs MADARIAGA,SANDRA T CONTRERAS,J.GUILLERMO SEGUEL,C.GLORIA INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS
description	Ab initio calculations at the MP2/6-31G** level have been carried out on the non-Watson-Crick nucleic acids pairs G<FONT FACE=Symbol>·</FONT>U and U<FONT FACE=Symbol>·</FONT>U to obtain the interaction energies and to see whether the derived values are comparable or not with the canonical G-C, A-T and A-U pairs. Optimized geometries of the pairs show that the structural parameters of the isolated bases differ very little on pairing. The guanine -NH2 group does not participate in the hydrogen bonding formation and possesses a pyramidal structure; its intrinsic nonplanarity plays an important role in the out-of-plane intermolecular interactions. Thus, the G<FONT FACE=Symbol>·</FONT>U pair projects three hydrogen bonding acceptor sites, namely, N7(G), O6(G) and O4(U) to the RNA major groove. The interaction energy (DHºint) calculated for the G<FONT FACE=Symbol>·</FONT>U pair (-13.6 kcal/mol) is comparable to that determined for A-T (-13.0 kcal/mol), but considerable smaller than the experimental value reported for G-C (-21.0 kcal/mol). The U<FONT FACE=Symbol>·</FONT>U pair follows the trend that pairing between pyrimidines bases should have lower interacting energies than purine-pyrimidine pairs
author	MADARIAGA,SANDRA T CONTRERAS,J.GUILLERMO SEGUEL,C.GLORIA
author_facet	MADARIAGA,SANDRA T CONTRERAS,J.GUILLERMO SEGUEL,C.GLORIA
author_sort	MADARIAGA,SANDRA T
title	INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS
title_short	INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS
title_full	INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS
title_fullStr	INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS
title_full_unstemmed	INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS
title_sort	interaction energies in non watson-crick pairs: an ab initio study of g·u and u·u pairs
publisher	Sociedad Chilena de Química
publishDate	2005
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072005000100013
work_keys_str_mv	AT madariagasandrat interactionenergiesinnonwatsoncrickpairsanabinitiostudyofgmiddotuandumiddotupairs AT contrerasjguillermo interactionenergiesinnonwatsoncrickpairsanabinitiostudyofgmiddotuandumiddotupairs AT seguelcgloria interactionenergiesinnonwatsoncrickpairsanabinitiostudyofgmiddotuandumiddotupairs
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INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G&middot;U AND U&middot;U PAIRS

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