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Table 1. Effect of poly(dG-dC)2 and
poly(dA-dT)2 on circular dichroism, electronic absorption and fluorescence
spectra for porphyrins P2 and P3. Positions of CD extrema are accompanied by
De (M-1 cm-1) in parentheses.
Fluorescence spectra were measured in the region 550 nm - 900 nm using lexc = 520 nm
| |
R |
CD spectrum
l /nm (De/M-1 cm-1
) |
Absorption a)
l max/nm (e /mM-1
cm-1) |
Fluorescence l max/nm
|
| P2/methanol |
- |
- |
416 (410) b) |
655, 720 |
| P3/methanol |
- |
- |
416 (280) b) |
654, 720 |
| P2/buffer |
- |
- |
406, 424, 436 (78) |
659, 722 c) |
| P3/buffer |
- |
- |
406, 418, 430 (56) |
656, 721 c) |
| P2/ poly(dA-dT)2 |
0.027 |
422 (3.8); 438 (-3.7) |
406, 425, 437 (84) |
661, 723 |
| P3/ poly(dA-dT)2 |
0.027 |
437 (3.8)
415 (1.3); 427 (-1.5) |
407, 422, 434 (54) |
658, 721 |
| P2/ poly(dG-dC)2 |
0.036 |
424 (3.3); 440 (-4.5) |
404, 438 (65) |
660, 724 |
| P3/poly(dG-dC)2 |
0.028 |
424 (2.9); 436 (-2.1) |
406, 418, 437 (37) |
657, 723 |
a) The Soret bands were
resolved into Gaussian curves in order to estimate the molar absorptivity e (in parentheses)
of the aggregate peaking above 430
nm.
b) The Soret band of the porphyrin
monomer; a vibrational shoulder is at about 400 nm.
c) The position of the peaks is not
influenced by aggregation and by the excitation wavelength.
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