DNA-mediated charge transport requires conformational motion of the DNA bases: elimination of charge transport in rigid glasses at 77 K.
Identifieur interne : 002365 ( PubMed/Curation ); précédent : 002364; suivant : 002366DNA-mediated charge transport requires conformational motion of the DNA bases: elimination of charge transport in rigid glasses at 77 K.
Auteurs : Melanie A. O'Neill [États-Unis] ; Jacqueline K. BartonSource :
- Journal of the American Chemical Society [ 0002-7863 ] ; 2004.
Descripteurs français
- KwdFr :
- MESH :
English descriptors
- KwdEn :
- MESH :
- chemical , chemistry : 2-Aminopurine, DNA.
- Cold Temperature, Fluorescence Polarization, Nucleic Acid Conformation, Spectrometry, Fluorescence.
Abstract
We have proposed that DNA-mediated charge transport (CT) is gated by base motions, with only certain base conformations being CT-active; a CT-active conformation can be described as a domain, a transiently extended pi-orbital defined dynamically by DNA sequence. Here, to explore these CT-active conformations, we examine the yield of base-base CT between photoexcited 2-aminopurine (Ap*) and guanine in DNA in rigid LiCl glasses at 77 K, where conformational rearrangement is effectively eliminated. Duplex DNA assemblies (35-mers) were constructed containing adenine bridges Ap(A)nG (n = 0-4). The yield of CT was monitored through fluorescence quenching of Ap* by G. We find, first, that the emission intensity of Ap* in all DNA duplexes increases dramatically upon cooling and becomes comparable to free Ap*. This indicates that all quenching of Ap* in duplex DNA is a dynamic process that requires conformational motion of the DNA bases. Second, DNA-mediated CT between Ap* and G is not observed at 77 K; rather than hindering the ability of DNA to transport charge, conformational motion is required. Moreover, the lack of DNA-mediated CT at 77 K, even through the shortest bridge, suggests that the static structures adopted upon cooling do not represent optimum CT-active conformations. These observations are consistent with our model of conformationally gated CT. Through conformational motion of the DNA bases, CT-active domains form and break-up transiently, both facilitating and limiting CT.
DOI: 10.1021/ja0455897
PubMed: 15479072
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Barton</name></author></titleStmt><publicationStmt><idno type="wicri:source">PubMed</idno><date when="2004">2004</date><idno type="RBID">pubmed:15479072</idno><idno type="pmid">15479072</idno><idno type="doi">10.1021/ja0455897</idno><idno type="wicri:Area/PubMed/Corpus">002365</idno><idno type="wicri:explorRef" wicri:stream="PubMed" wicri:step="Corpus" wicri:corpus="PubMed">002365</idno><idno type="wicri:Area/PubMed/Curation">002365</idno><idno type="wicri:explorRef" wicri:stream="PubMed" wicri:step="Curation">002365</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en">DNA-mediated charge transport requires conformational motion of the DNA bases: elimination of charge transport in rigid glasses at 77 K.</title><author><name sortKey="O Neill, Melanie A" sort="O Neill, Melanie A" uniqKey="O Neill M" first="Melanie A" last="O'Neill">Melanie A. O'Neill</name><affiliation wicri:level="1"><nlm:affiliation>Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.</nlm:affiliation><country xml:lang="fr">États-Unis</country><wicri:regionArea>Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125</wicri:regionArea></affiliation></author><author><name sortKey="Barton, Jacqueline K" sort="Barton, Jacqueline K" uniqKey="Barton J" first="Jacqueline K" last="Barton">Jacqueline K. Barton</name></author></analytic><series><title level="j">Journal of the American Chemical Society</title><idno type="ISSN">0002-7863</idno><imprint><date when="2004" type="published">2004</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>2-Aminopurine (chemistry)</term><term>Cold Temperature</term><term>DNA (chemistry)</term><term>Fluorescence Polarization</term><term>Nucleic Acid Conformation</term><term>Spectrometry, Fluorescence</term></keywords><keywords scheme="KwdFr" xml:lang="fr"><term>ADN ()</term><term>Amino-2 purine ()</term><term>Basse température</term><term>Conformation d'acide nucléique</term><term>Polarisation de fluorescence</term><term>Spectrométrie de fluorescence</term></keywords><keywords scheme="MESH" type="chemical" qualifier="chemistry" xml:lang="en"><term>2-Aminopurine</term><term>DNA</term></keywords><keywords scheme="MESH" xml:lang="en"><term>Cold Temperature</term><term>Fluorescence Polarization</term><term>Nucleic Acid Conformation</term><term>Spectrometry, Fluorescence</term></keywords><keywords scheme="MESH" xml:lang="fr"><term>ADN</term><term>Amino-2 purine</term><term>Basse température</term><term>Conformation d'acide nucléique</term><term>Polarisation de fluorescence</term><term>Spectrométrie de fluorescence</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">We have proposed that DNA-mediated charge transport (CT) is gated by base motions, with only certain base conformations being CT-active; a CT-active conformation can be described as a domain, a transiently extended pi-orbital defined dynamically by DNA sequence. Here, to explore these CT-active conformations, we examine the yield of base-base CT between photoexcited 2-aminopurine (Ap*) and guanine in DNA in rigid LiCl glasses at 77 K, where conformational rearrangement is effectively eliminated. Duplex DNA assemblies (35-mers) were constructed containing adenine bridges Ap(A)nG (n = 0-4). The yield of CT was monitored through fluorescence quenching of Ap* by G. We find, first, that the emission intensity of Ap* in all DNA duplexes increases dramatically upon cooling and becomes comparable to free Ap*. This indicates that all quenching of Ap* in duplex DNA is a dynamic process that requires conformational motion of the DNA bases. Second, DNA-mediated CT between Ap* and G is not observed at 77 K; rather than hindering the ability of DNA to transport charge, conformational motion is required. Moreover, the lack of DNA-mediated CT at 77 K, even through the shortest bridge, suggests that the static structures adopted upon cooling do not represent optimum CT-active conformations. These observations are consistent with our model of conformationally gated CT. Through conformational motion of the DNA bases, CT-active domains form and break-up transiently, both facilitating and limiting CT.</div></front></TEI><pubmed><MedlineCitation Status="MEDLINE" Owner="NLM"><PMID Version="1">15479072</PMID><DateCompleted><Year>2005</Year><Month>04</Month><Day>19</Day></DateCompleted><DateRevised><Year>2008</Year><Month>11</Month><Day>21</Day></DateRevised><Article PubModel="Print"><Journal><ISSN IssnType="Print">0002-7863</ISSN><JournalIssue CitedMedium="Print"><Volume>126</Volume><Issue>41</Issue><PubDate><Year>2004</Year><Month>Oct</Month><Day>20</Day></PubDate></JournalIssue><Title>Journal of the American Chemical Society</Title><ISOAbbreviation>J. Am. Chem. Soc.</ISOAbbreviation></Journal><ArticleTitle>DNA-mediated charge transport requires conformational motion of the DNA bases: elimination of charge transport in rigid glasses at 77 K.</ArticleTitle><Pagination><MedlinePgn>13234-5</MedlinePgn></Pagination><Abstract><AbstractText>We have proposed that DNA-mediated charge transport (CT) is gated by base motions, with only certain base conformations being CT-active; a CT-active conformation can be described as a domain, a transiently extended pi-orbital defined dynamically by DNA sequence. Here, to explore these CT-active conformations, we examine the yield of base-base CT between photoexcited 2-aminopurine (Ap*) and guanine in DNA in rigid LiCl glasses at 77 K, where conformational rearrangement is effectively eliminated. Duplex DNA assemblies (35-mers) were constructed containing adenine bridges Ap(A)nG (n = 0-4). The yield of CT was monitored through fluorescence quenching of Ap* by G. We find, first, that the emission intensity of Ap* in all DNA duplexes increases dramatically upon cooling and becomes comparable to free Ap*. This indicates that all quenching of Ap* in duplex DNA is a dynamic process that requires conformational motion of the DNA bases. Second, DNA-mediated CT between Ap* and G is not observed at 77 K; rather than hindering the ability of DNA to transport charge, conformational motion is required. Moreover, the lack of DNA-mediated CT at 77 K, even through the shortest bridge, suggests that the static structures adopted upon cooling do not represent optimum CT-active conformations. These observations are consistent with our model of conformationally gated CT. Through conformational motion of the DNA bases, CT-active domains form and break-up transiently, both facilitating and limiting CT.</AbstractText></Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>O'Neill</LastName><ForeName>Melanie A</ForeName><Initials>MA</Initials><AffiliationInfo><Affiliation>Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Barton</LastName><ForeName>Jacqueline K</ForeName><Initials>JK</Initials></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D013485">Research Support, Non-U.S. Gov't</PublicationType><PublicationType UI="D013487">Research Support, U.S. Gov't, P.H.S.</PublicationType></PublicationTypeList></Article><MedlineJournalInfo><Country>United States</Country><MedlineTA>J Am Chem Soc</MedlineTA><NlmUniqueID>7503056</NlmUniqueID><ISSNLinking>0002-7863</ISSNLinking></MedlineJournalInfo><ChemicalList><Chemical><RegistryNumber>452-06-2</RegistryNumber><NameOfSubstance UI="D015075">2-Aminopurine</NameOfSubstance></Chemical><Chemical><RegistryNumber>9007-49-2</RegistryNumber><NameOfSubstance UI="D004247">DNA</NameOfSubstance></Chemical></ChemicalList><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D015075" MajorTopicYN="N">2-Aminopurine</DescriptorName><QualifierName UI="Q000737" MajorTopicYN="Y">chemistry</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D003080" MajorTopicYN="N">Cold Temperature</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004247" MajorTopicYN="N">DNA</DescriptorName><QualifierName UI="Q000737" MajorTopicYN="Y">chemistry</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D005454" MajorTopicYN="N">Fluorescence Polarization</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D009690" MajorTopicYN="N">Nucleic Acid Conformation</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D013050" MajorTopicYN="N">Spectrometry, Fluorescence</DescriptorName></MeshHeading></MeshHeadingList></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="pubmed"><Year>2004</Year><Month>10</Month><Day>14</Day><Hour>9</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2005</Year><Month>4</Month><Day>20</Day><Hour>9</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="entrez"><Year>2004</Year><Month>10</Month><Day>14</Day><Hour>9</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">15479072</ArticleId><ArticleId IdType="doi">10.1021/ja0455897</ArticleId></ArticleIdList></PubmedData></pubmed></record>Pour manipuler ce document sous Unix (Dilib)
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