Studies on the Interaction between Copper( ) Complex with Phenanthroline and L2Methionine Ligands and D NA

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1 , ACTA CHIMICA SINICA Vol 61, 2003 No 2, ( ) DNA a, b c b a Ξ, a b b b Ξ ( a ) ( b ) ( c ) ph = 6186, ( ) ( EB) [ Cu (phen) ( H 2 O) ( L2Met) ] + (phen = 1,102, L2Met = L2 ) DNA 1 DNA,,,,, EB2DNA [ Cu (phen) ( H 2 O) ( L2Met) ] + DNA, ( ),,, DNA, Studies on the Interaction between Copper( ) Complex with Phenanthroline and L2Methionine Ligands and D NA LI, Hong a, b LE, Xue2Yi c WU, Jian2Zhong b LIU, Jie a J I, Liang2Nian Ξ, a J IANG, Xiong b LI, Wei2Shan b XU, Zheng2He b ( a School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou ) ( b Department of Chemistry, South China Normal University, Guangzhou ) ( c College of Science, South China Agricultural University, Guangzhou ) Abstract The interaction between [ Cu (phen) ( H 2 O) ( L2Met) ] + methionine) and calf thymus DNA in phosphate buffer ( ph = 6186) (phen = 1,102phenanthroline and L2Met = L2 has been investigated by electrochemical techniques ( cyclic voltammetry, differential pulse voltammetry, ac impedance and its data fitting), viscosity measurements, electronic absorption and ethidium bromide ( EB) fluorescene spectroscopy A quasi2reversible redox wave for the central copper ion from the cyclic voltammograms is shown at a plantium electrode It has been found that the values of the reduction peak current and apparent diffusion coefficient decreased significantly in the presence of DNA compared with that in the absence of DNA, and the electrochemical reaction resistance values increased, the maximal absorption peaks from absorption spectra are red2shifted and the intensity is weakened At the same time, [Cu (phen) ( H 2 O) ( L2Met) ] + can remarkably quench the emission intensity of EB2DNA system All experimental results indicate that the interaction of [ Cu (phen) ( H 2 O) ( L2Met) ] + intercalation is proved to exist with calf thymus DNA is strong and the part Keywords copper ( ) complex, phenanthroline, methionine, calf thymus DNA, intercalation Ξ E2mail : edu cn Received April 3, 2002 ; revised August 2, 2002 ; accepted November 11, 2002 (No ) (Nos , )

2 246 Vol 61, 2003 DNA : 0, 01026, 01064, 01128, 01255, 01383,, mmol L DNA [1 4] Sigman (phen) DNA, (30 011), DNA, 0145 mmol L - 1, [5 DNA,6] ; phen, [7] [13 ] - (O 2 ),, (18 2) [8,9] ; Schiff, [10] 2 1 DNA [ Cu (phen) ( H 2 O) ( L2Met) ] + (phen = 1,102 ph = 6186, [ Cu (phen) 2, L2Met = L2 ) ( H 2 O) ( L2Met) ] V DNA, 1 ( 1), 011 V s - 1, E p,c V, E p,a V, E V, E p V, 1 ( 4), 1 1 1, Autolab PGSTAT30, EG&G M173 Π [13] [ Cu (phen)2 M175, YEW3086X2Y,UV2Vis 8500 Π ( H 2 O) ( L2Met) ] cm 2 s - 1,, F22500,pHS23C,, [ Cu(phen) ( H 2 O) ( L2Met) ]NO 3 H 2 O [11], ; DNA, 0105 mol L - 1 (ph = 6186), DNA [12 ] , Pt, 0124 cm 2, Pt, (SCE), 013 mmol L min, [ Cu(phen) ( H 2 O) ( L2Met) ] + DNA, 3 ml, 0101 mmol L - 1, Figure 1 Cyclic voltammograms of [ Cu(phen) (H 2 O) (L2Met) ] + as nm, 10 L a function of DNA 10 L DNA, 8 R = [DNA]Π[ Cu], 100 mv s - 1 min nm 15 nm s ΠDNAΠ ( EB) 550, nm 418 mol L - 1, DNA 515 mol L - 1, 2 ( 2A), ( V s - 1 ), 1 DNA [ Cu(phen) ( H 2 O) ( L2 Met) ] +, DNA, R = 6, 011 V s - 1, E p,c

3 No 2 : ( ) DNA V, E p,a V, E V, E p V, DNA,, DNA, ( 2B),, R = 6, [ Cu(phen) ( H 2 O) ( L2Met) ] cm 2 s - 1 ( 4), DNA R = 6, E 0 [12 DNA 17 mv,,14] : E 0 = E 0 b - Ef 0 = 59115lg( K R ΠK O ) 3 [ Cu(phen) ( H Ef 0 E 0 2 O) ( L2Met) ] + DNA b DNA, K R K O Figure 3 Differential pulse voltammograms of [ Cu(phen) (H 2 O) (L2 DNA K R ΠK O = Met) ] + as a function of DNA 1194, [ Cu(phen) ( H 2 O) ( L2Met) ] + DNA modulation amplitude : 25 mv, step potential : 5 mv 4 Figure 4 Plots of reduction peak current vs square root of scan rate 5 DNA V ( Hz) 2 Figure 5 The complex impedance plots of [ Cu (phen) ( H 2 O) ( L2 Figure 2 Influences of scan rate on CV diagrams Met) ] + as a function of DNA ( Hz) scan rate (mv s - 1 ) : (A) R = 0, (B) R = 6 ; 1 200, 2 100, 3 50, 4 20, [ Cu(phen) ( H 2 O) ( L2Met) ] + DNA

4 248 Vol 61, 2003, DNA, Autolab DNA V ( 6) ( 1) 1, DNA, R ct C dl,, DNA,,,, R ct,,, C dl 6 [ Cu(phen) (H 2 O) (L2Met) ] + Figure 6 Equivalent circuit for reaction of [ Cu(phen) ( H 2 O) ( L2 2 DNA [ Cu(phen) (H 2 O) ( L2Met) ] + Met) ] + at a platinum electrode Table 2 Effects of DNA on the maximal absorption peaks for 1 DNA [ Cu (phen) ( H 2 O) ( L2Met) ] + c (DNA)Π(mmol L - 1 ) a Table 1 Values of each element in the equivalent circuit for [Cu(phen)2 (H 2 O) (L2Met) ] + as a function of DNA concentration a R R ct Π(k cm 2 ) C dl Π( F cm 2 ) n a R ct, C dl, n 1 2, R = 1114 EB 7 [ Cu(phen) ( H 2 O) ( L2Met) ] + DNA Figure 7 Absorption spectra of [ Cu(phen) ( H 2 O) ( L2Met) ] + function of DNA concentration [ Cu(phen) (H 2 O) ( L2Met) ] + from absorption spectra, EB EB2DNA, 2 2 DNA EB2DNA, EB DNA, DNA 8 2 6,,, DNA, EB2DNA, [15], DNA, DNA, EB DNA, 3, phen DNA,, 3, ; EB EB2DNA, 3, 3, [16] : EB2DNA 7 DNA, 50 %, DNA nm 205, nm 100,, DNA 3 n 3, F EB2DNA, F 0 R = 6, 17 %( DNA EB2DNA,[ Cu ], DNA ) ; R RF = FΠF 0, RC = [ Cu ]Πc DNA = 12, 28 %, DNA, EB2DNA ( 2), [ Cu (phen) ( H 2 O) ( L2Met) ] + ( 9) 9, [ Cu (phen) ( H 2 O) ( L2Met) ] + DNA DNA, as a max Πnm DNA ( EB) EB, DNA, DNA, EB2DNA EB EB 8 DNA 315 DNA

5 No 2 : ( ) DNA 249, DNA 8 [ Cu(phen) (H 2 O) ( L2Met) ] + EB2DNA Figure 8 Fluorescence spectra of EB2DNA system with various concentration of [ Cu(phen) (H 2 O) (L2Met) ] + ex = 525 nm, [ Cu]Π(mmol L - 1 ) : 1 0 (in absence of DNA), 2 0, , , , DNA [ Cu (phen) ( H 2 O) ( L2Met) ] + Figure 10 Effects of the addition of increasing amounts of [ Cu(phen) (H 2 O) (L2Met) ] + on the specific relative viscosity of 7 Pfau, J ; Arvidson, D N ; Youderian, P ; Pearson, L ; 9 [ Cu(phen) (H 2 O) (L2Met) ] + EB2DNA Sigman, D S Biochemistry 1994, 33, Xiang, Y ; Lu, C2S Acta Biochim Biophys Sinica 1992, Figure 9 Effects of [ Cu(phen) (H 2 O) (L2Met) ] + on the 24, 117 (in Chinese) fluorescence spectra of EB2DNA system (,,, 1992, 24, 117 ) 2 4 DNA DNA 247, 8439 [17,18] ( Π 0 ) 1Π3 [ Cu(phen) ( H 2 O) ( L2Met) ] + ( 0 (in Chinese) DNA ),,DNA (,,, ( 10) phen DNA 1023, (,,, 2002, 18, 1023 ) ( EB) 12 Cater, M T ; Rodriguez, M ; Bard, A J J phen, Met H 2 O Soc 1989, 111, 8901 Am Chem DNA References 1 Barton, J K Science 1986, 233, Yang, P ; Song, Y2F Prog Chem 2000, 12, 31 ( in Chinese) (,,, 2000, 12, 31 ) 3 Liu, J 2G ; Ji, L2N Chin J Inorg Chem 2000, 16, 195 (in Chinese) (,,, 2000, 16, 195 ) 4 Sardesai, N Y ; Zimmermann, K ; Barton, J K J Am Chem Soc 1994, 116, Sigman, D S ; Graham, D R ; D Aurora, V ; Stern, A M J Biol Chem 1979, 254, Sigman, D S Acc Chem Res 1986, 19, Klug, D ; Rabani, J ; Fridovich, I J Biol Chem 1972, 10 Bi, S2W; Liu, S2X Chin J Inorg Chem 1996, 12, 423, 1996, 12, 423 ) 11 Le, X2Y ; Tong, M2L Chin J Inorg Chem 2002, 18,

6 250 Vol 61, Satyanaryana, S ; Daborwiak, J C ; Chaires, J B Biochemistry 1993, 32, Dong, S2J ; Zhang, D2B Acta Chim Sinica 1988, 46, 335 (in Chinese) (,,, 1988, 46, 335 ) 15 Tysoe, S A ; Baker, A D ; Strekas, T C J Phys Chem 1993, 97, Li, Z2L ; Chen, J 2L ; Zhang, K2C ; Li, M2L ; Yu, R 2Q Sci China, Ser B 1991, 11, 1193 (in Chinese) (,,,,, (B), 1991, 11, 1193 ) 17 Sigma, D S ; Mazuder, A ; Perrin, D M Chem Rev 1993, 93, Zou, X2H ; Ye, B2H ; Li, H ; Zhang, Q2L ; Chao, H ; Liu, J 2G ; Ji, L2N ; Li, X2Y J Biol Inorg Chem 2001, 6, 143 (A ZHAO, X J ; DONG, H Z )