DNA binding and cleaving activity of the new cleft molecule N,N'-Bis(guanidinoethyl)-2,6-pyridinedicarboxamide in the absence or in the presence of copper(II).
Novel cleft molecule pyridine-2,6-dicarboxamide appending two guanidinoethyl group side arms (Gua) was synthesized. The interactions of the cleft molecule in the absence of copper(II) (Gua) or in the presence of copper(II) (Cu2+-Gua) with calf thymus DNA were studied by fluorescence and CD spectroscopy. The results indicate that the DNA binding affinity of Cu2+-Gua is stronger than that of Gua, and the binding constants of Cu2+-Gua and Gua are 1.61 x 10(6) M(-1) and 2.86 x 10(5) M(-1), respectively. Agarose gel electrophoresis was used to assess the plasmid pUC 19 DNA cleavage activities in the presence of Gua and Cu2+-Gua. Kinetic data of DNA cleavage promoted by Cu2+-Gua under physiological conditions fit a saturation kinetic profile with k(max) of 0.0173 +/- 0.0011 h(-1), which gave a aproximately 10(6)-fold rate acceleration over uncatalyzed supercoiled DNA, while the catalyst concentration is lower than 0.0625 mM. The hydrolysis pathway was proposed as the possible mechanism for DNA cleavage promoted by Cu2+-Gua. The acceleration is due to efficient cooperative catalysis of the copper cation center and the functional groups (bis(guanidinium) groups).
Shao
Ying
Y
Department of Chemistry, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, People's Republic of China.
Sheng
Xin
X
Li
Ying
Y
Jia
Zhao-Li
ZL
Zhang
Jing-Jing
JJ
Liu
Fang
F
Lu
Guo-Yuan
GY
D002384:Catalysis; D002413:Cations, Divalent / Q000737:chemistry; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D053837:DNA Cleavage; D019791:Guanidine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D011728:Pyridones / Q000138:chemical synthesis*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D002413:Cations, Divalent; C533574:N,N'-bis(guanidinoethyl)-2,6-pyridinedicarboxamide; D011728:Pyridones; D003300:Copper; D004247:DNA; C427203:calf thymus DNA; D019791:Guanidine