Binding of Ru(bpy)2(eilatin)2+ to matched and mismatched DNA.
The DNA-binding properties of Ru(bpy)2(eilatin)(2+) have been investigated to determine if the sterically expansive eilatin ligand confers specificity for destabilized single-base mismatches in DNA. Competitive DNA photocleavage experiments employing a sequence-neutral metallointercalator, Rh(bpy)2(phi)(3+) (phi = 9,10-phenanthrenequinonediimine), and a mismatch-specific metalloinsertor, Rh(bpy)2(chrysi)(3+) (chrysi = chrysene-5,6-quinonediimine), reveal that the eilatin complex binds to a CC mismatched site with an apparent binding constant of 2.2(2) x 10(6) M(-1). Nonetheless, the selectivity in binding mismatched DNA is not high: competitive titrations with Rh(bpy)2(phi)(3+) show that the complex binds also to well-matched B-form sites. Thus, Ru(bpy)2(eilatin)(2+), despite containing the extremely expansive eilatin ligand, displays lower selectivity for the mismatch than does Rh(bpy)2(chrysi)(3+), a metalloinsertor containing the smaller, though still bulky, chrysene-5,6-quinonediimine ligand. In summary, the size and shape of the eilatin ligand allow stacking with both well-matched and mismatched DNA.
Zeglis
Brian M
BM
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Barton
Jacqueline K
JK
D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*
D009942:Organometallic Compounds; C478001:lambda-(bis(2,2'-bipyridine)(eilatin)ruthenium(II)); D004247:DNA