Binding of meso-Tetrakis(N-methylpyridinium-4-yl)porphyrin to AT Oligomers: Effect of Chain Length and the Location of the Porphyrin Stacking

Jin Ok Kim, Young Ae Lee, Byeong Hwa Yun, Sung Wook Han, Sam Tag Kwag, Seog K. Kim

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Circular dichroism (CD) spectra of meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) that are associated with various duplex and triplex AT oligomers were investigated in this study. A strong positive CD was apparent for both the TMPyP complexed with duplex d[(A-T)12]2, d(A)12·d(T)12 and triplex d(A)12·d[(T)12]2 at a low mixing ratio. As the mixing ratio increased, bisignate excitonic CD was produced for TMPyP complexed with duplexes, whereas the positive CD signal remained the same for the TMPyP-d(A)12·d[(T) 12]2 complex. This difference in the CD spectrum in the presence of duplex and triplex oligomers indicates that the moderate stacking of TMPyP occurs at the major groove of the duplex and the monomeric binding occurs in (or near) the minor groove. When TMPyP forms a complex with duplex d[(A-T)6]2 only excitonic CD was observed, even at a very low mixing ratio. Therefore, at least seven or more basepairs are required for TMPyP to exhibit a monomeric CD spectrum. After close analysis of the CD spectrum, the TMPyP-poly[d(A-T)2] complex could be explained by a combination of the CD spectrum of the monomeric, moderately stacked, and extensively stacked TMPyP.

Original languageEnglish (US)
Pages (from-to)1012-1017
Number of pages6
JournalBiophysical journal
Volume86
Issue number2
DOIs
StatePublished - Feb 2004

Bibliographical note

Funding Information:
This study was supported by a Yeungnam University internal research grant (2002) conferred to the Advance Research Center for Gene Selective Reaction.

Fingerprint Dive into the research topics of 'Binding of meso-Tetrakis(N-methylpyridinium-4-yl)porphyrin to AT Oligomers: Effect of Chain Length and the Location of the Porphyrin Stacking'. Together they form a unique fingerprint.

Cite this