Chlorobenzylidine-calf thymus DNA interaction II: circular dichroism and nuclear magnetic resonance studies.
The binding of chlorobenzylidine to calf thymus DNA has been studied in detail by means of circular dichroism (CD), nuclear magnetic resonance (1H NMR), viscosimetry and denaturation temperature (Tm). Chlorobenzylidine is found to intercalate between base pairs of DNA as evidence by: (1) induced circular dichroism; (2) broadened 1H NMR signals; (3) enhanced viscosity; and (4) increased denaturation temperature of the DNA helix. In addition, Scatchard plot from CD titration data gives a binding constant of 2.6 x 10(4) M(-1) and a binding site size of 4 base pairs at 25 degrees C. Matrix rank analysis shows that there are three main components contributing to the observed CD spectra. The nuclear magnetic resonance experiment shows that the planar aromatic ring of tetrahydroberberine group in chlorobenzylidine intercalates between the base pairs of DNA when chlorobenzylidine is bound to DNA.
Zhong
Wenying
W
State Key Laboratory of Coordination Chemistry, Nanjing University, 210093, China.
Yu
Jun-Sheng
JS
Liang
Yingqiu
Y
Fan
Keqiang
K
Lai
Luhua
L
D000818:Animals; D001597:Benzylidene Compounds; D002417:Cattle; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D011083:Polycyclic Compounds / Q000737:chemistry* / Q000378:metabolism*; D013696:Temperature; D013816:Thermodynamics; D017186:Titrimetry; D014783:Viscosity
D001597:Benzylidene Compounds; D011083:Polycyclic Compounds; C451700:chlorobenzylidine; D004247:DNA; C427203:calf thymus DNA