Selective recognition of consecutive G sequence in double-stranded DNA by a Zinc(II)-macrocyclic tetraamine complex appended with an anthraquinone

A zinc (II) complex with a macrocyclic tetraamine appended with an anthraquinone ((9,10-anthraquinon-2-yl)methyl-1,4,7,10- tetraazacyclododecane, ZnL, anthraquinonyl-cyclen) selectively recognizes consecutive G sequence in double-stranded DNA. The affinity of the Zn2+-anthraquinonyl-cyclen to consecutive dG groups in DNA was disclosed by comparison of K-app values (=[DNA-bound ZnL]/[uncomplexed ZnL][uncomplexed nucleobase in DNA]) determined by the UV spectrophotometric titrations at pH 8, I=0.1 (NaNO3), and 25 degreesC for poly(dG)(.)poly(dC) (K-app=1.5X10(5) M-1)(2) poly(dG-dC)(2) (2.8x10(4) M-1), poly(dA-dT)(2) (4.3x10(4) M-1), and calf thymus DNA (2.8x10(4) M-1). The corresponding K-app values with the Zn2+-free ligand were 5.3x10(3) M-1, 7.4x10(3) M-1, 7.4x10(3) M-1, and 5.9x10(3) M-1, respectively. The selective recognition of consecutive G sequence was concluded from the DNase I footprinting of SV40 early promotor DNA fraction (197 bp) containing a TATA box and six GC boxes. The present finding is in remarkable contrast to the previous selective T-recognition by Zn2+-cyclen complexes appended with acridine, quinoline(s), and naphthalene(s) [J. Am. Chem. Sec. 121 (1999) 5426]. While the Zn2+-acridinyl-cyclen inhibited TATA binding protein from interacting with a TATA box consensus DNA [J. Inorg. Biochem. 79 (2000) 253], the present Zn2+-anthraquinonyl-cyclen inhibited the Spl transcriptional factor protein from interacting with a GC box-consensus DNA. (C) 2000 Elsevier Science B.V. All rights reserved.