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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
6
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pubmed:dateCreated |
1997-4-30
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pubmed:abstractText |
In contrast to shorter homologs which only form a single-stranded nucleic acid alpha-helix in acid solution at [Na+]</=0.02 M Na+, d(A-G)20,30 form in addition a parallel-stranded duplex with (A+.A+) and (G.G) base pairs and interstrand dA+...PO2-ionic and dA+NH2... O=P H-bonds. Under conditions where duplex prevails over alpha-helix, the contribution of the base-backbone interactions to stability varies directly with [H+] and inversely with [Na+], just as in poly(A+.A+). These duplexes are characterized by intense circular dichroism and a large cooperative thermally-induced hyperchromic transition that is dependent on oligomer concentration. Dimethylsulfate reactivity of the dG residues indicates G.G and therefore dA+.dA+rather than dA+.G base pairs. At much higher ionic strength (Na+>/=0.2 M) the protonated base-backbone interactions are so weakened that duplex stability becomes increasingly dependent upon H-bonded base pairing and stacking and almost independent of pH. Between pH 6 and 8 this duplex structure is devoid of protonated dA residues and shows positive dependence of T m on ionic strength similar to that of DNA.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-13741242,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-13824904,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-1396571,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-1409629,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-1701219,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-1738588,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-2181446,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-2754734,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-3271438,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-3310237,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-5231750,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-6159589,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-7578032,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-7578033,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-8255779,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-8399154,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-8404869,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-8411173,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-9016674,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092616-958482
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0305-1048
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
25
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1100-7
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
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pubmed:year |
1997
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pubmed:articleTitle |
Parallel-stranded linear homoduplexes of d(A+-G)n > 10 and d(A-G)n > 10 manifesting the contrasting ionic strength sensitivities of poly(A+.A+) and DNA.
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pubmed:affiliation |
Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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