Table 1. Sugar radicals formed via photo-excitation of one-electron oxidized dinucleoside phosphates and oligonucleotides at 143K a,b,c.
Compound | Percent convertedd | Init. Rate (%/min) | C1′•e | C3′• e | C5′• e | |
---|---|---|---|---|---|---|
No filter | ≥540 nm | |||||
dGuof | 90 | 4.2 | 3.5 | 10 | 35 | 55 |
8-D-dGuof | 90 | 4.0 | - | 10 | 35 | 55 |
8-D-3′-dGMPf | 85 | 1.9 | - | 40 | - | 60 |
8-D-3′-dGMP(77 K)f | 15 | 0.08 | - | 40 | - | 60 |
5′-dGMPf | 95 | 4.0 | - | 95 | 5 | - |
5′-dGMP (77 K)f | 30 | 1.0 | - | 15 | 30 | 55 |
TpdGg | 85 | 4.0 | - | 90 | 10 | - |
dGpdG | 90 | 2.5 | - | 35 | 5 | 60 |
AGA | 50 | 0.5 | - | 20 | 20 | 60 |
TGT | 95 | 2.0 | 0.4 | 40 | 5 | 50 |
TGGT | 75 | 1.2 | 0.7 | 30 | 10 | 60 |
5′-p-TGGT | 80 | 1.2 | 0.8 | 30 | 10 | 60 |
TGGGT | 70 | 1.0 | - | 60 | - | 40 |
AGGGAh | 80 | 1.2 | - | 10h | 20h | 30h |
TTGTT | 75 | 0.8 | - | 50 | 10 | 40 |
TTGGTT | 55 | 1.1 | - | 50 | 7 | 43 |
TTGGTTGGTT | 55 | ca. 0.6 | 0.15 | 60 | - | 40 |
dsDNA (ice) i | 40 | 0.26 | 0.07 | 100 | - | - |
Radical percentages expressed to ±10% relative error. Initial rates are based on the % G•+ converted to sugar radicals after the first 20 min of visible light exposure and should be consider as indicative of the relative rates of sugar radical formation.
All glassy samples are at the native pH of 7.5 M LiCl (ca. 5).14
All samples were illuminated at 143 K unless indicated otherwise.
Percentage of conversion of one-electron oxidized dinucleoside phosphate or oligonucleotide to sugar radicals. The total spectral intensities before and after illumination were the same, within experimental uncertainties.
Each calculated as percentage of total sugar radical concentration; these sum to 100%.
The overall spectrum obtained after photo-excitation has also an underlying unidentified spectrum (ca. 40%).
DNA (salmon testes) in a frozen aqueous (D2O) solution (ice).