Interaction of metallo- and free base meso-tetrakis(N-methylpyridium-4-yl)porphyrin with a G-quadruplex: effect of the central metal ions.
The effects of the central metal ion on complex formation between meso-tetrakis(N-methylpyridium-4-yl)porphyrin (TMPyP) and the thrombin-binding aptamer G-quadruplex, 5'G2T2G2TGTG2T2G2, were examined in this study. The central metal ions were vanadium and zinc. At a [porphyrin]/[G-quadruplex] ratio of less than one, the absorption and CD spectra were unaffected by the mixing ratio for all three porphyrins, suggesting that the binding mode is homogeneous. Relatively small changes in the absorption spectrum when forming the complexes with the G-quadruplex, the positive CD signal, and the large accessibility of the I(-) quencher, suggested that all these porphyrins are not intercalated between the G-quartet. Stabilization of the G-quadruplex by ZnTMPyP was most effective. The effect of VOTMPyP on G-quadruplex stabilization was moderate, whereas TMPyP slightly destabilized G-quadruplex. From this observation, the involvement of the ligation of one G-quartet component to the central metal ion in G-quadruplex stabilization by metallo-TMPyP is suggested.
Department of Chemistry, Yeungnam University, 214 Dae-dong, Gyeongsan City, Gyeong-buk 712-749, Republic of Korea.
Yun-Hwa
YH
Kim
Department of Chemistry, Yeungnam University, 214 Dae-dong, Gyeongsan City, Gyeong-buk 712-749, Republic of Korea.
Changyun
C
Lee
Department of Chemistry, Yeungnam University, 214 Dae-dong, Gyeongsan City, Gyeong-buk 712-749, Republic of Korea. Electronic address: seogkim@yu.ac.kr.
Seog K
SK
Kim
Center for Medical Measurements, Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon 305-340, Republic of Korea. Electronic address: scjeung@kriss.re.kr.
Sae Chae
SC
Jeoung
D003300:Copper / Q000737:chemistry*; D054856:G-Quadruplexes; D007477:Ions / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D017968:Vanadium Compounds / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
D007477:Ions; D009942:Organometallic Compounds; D011166:Porphyrins; D017968:Vanadium Compounds; C540459:meso-tetrakis(N-methylpyridinium-4-yl)porphyrin; D003300:Copper; D015032:Zinc
Circular dichroism; DNA; Fluorescence; G-quadruplex; Porphyrin