Metal ion-directed cooperative DNA binding of small molecules

• Published in: Journal of inorganic biochemistry Vol. 100; no. 11; pp. 1744 - 1754
• Main Authors: Ihara, Toshihiro, Ikegami, Takashi, Fujii, Tomohiro, Kitamura, Yusuke, Sueda, Shinji, Takagi, Makoto, Jyo, Akinori
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-11-2006
• Subjects: Animals; Cations - chemistry; Cattle; Circular Dichroism; Cooperative DNA binding; Copper - chemistry; Dimerization; DNA - chemistry; DNA ligand; Ligands; Linear dichroism; Magnetic Resonance Spectroscopy; Metal-responsive DNA binding; Metallo-regulation; Metals - chemistry; Molecular Structure; Spectrometry, Mass, Electrospray Ionization; Spectrophotometry, Ultraviolet; Cooperative DNA binding; Linear dichroism; Metal-responsive DNA binding; DNA ligand; Metallo-regulation
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2006.06.008

Compound (1), which consists of an oxine and a pyridinium group, was synthesized as a metal-responsive DNA binding ligand. Two 1s coordinate to a Cu(II) to form a stable dimer (12–Cu), even in the presence of DNA. The binding of 1 with sonicated calf thymus DNA was enhanced by ca. 103 times after forming the dimer; the binding constants were estimated to be 3.2×104M−1 and 2.4×107M−1 in the absence and the presence, respectively, of a half mole of Cu(II). The enormous acceleration of the binding is partly attributed to the generation of a dicationic charge by the formation of the dimer. High cooperativity between dimers could be also responsible; dimers would gather along the duplex as a template to form 1D spiral aggregates.