Département de chimie moléculaire

A series of nine Ni(II) salophen complexes involving one, two, or three alkyl-imidazolium side-chains was prepd. The lengths of the side-chains were varied from one to three carbons. The crystal structure of one complex revealed a square planar geometry of the nickel ion. Fluorescence resonance energy transfer melting of G-quadruplex structures in the presence of salophen complex were performed. The G-quadruplex DNA structures were stabilized in the presence of the complexes, but a duplex DNA was not. The binding consts. of the complexes for parallel and antiparallel G-quadruplex DNA, as well as hairpin DNA, were measured by surface plasmon resonance. The compds. were selective for G-quadruplex DNA, as reflected by equil. dissocn. const. KD values in the region 0.1-1 $μ$M for G-quadruplexes and greater than 2 $μ$M for duplex DNA. Complexes with more and shorter side-chains had the highest binding consts. The structural basis for the interaction of the complexes with the human telomeric G-quadruplex DNA was investigated by computational studies: the arom. core of the complex stacked over the last tetrad of the G-quadruplex with peripherical cationic side chains inserted into opposite grooves. Biochem. studies (telomeric repeat amplification protocol assays) indicated that the complexes significantly inhibited telomerase activity with IC50 values as low as 700 nM; the complexes did not significantly inhibit polymerase activity. [on SciFinder(R)]