Table 1. Characterization of synthesized stable isotope labeled DNAs 30–38.
| Molecular weightd | ||||
|---|---|---|---|---|
| Sequencea | No. and type of 13C-labeled residuesb | Lengthc | Calculated (amu) | Found (amu) |
| HIV-1 PPT | ||||
| 30 | dT9 | 20 nt | 5969.8 | 5968.8 |
| 31 | dT1 | 20 nt | 5961.8 | 5961.1 |
| 32 | dT1 | 20 nt | 5961.8 | 5961.2 |
| mini cTAR | ||||
| 33 | dA4dC3dG4dT3 | 26 nt | 7975.1 | 7975.4 |
| full length cTAR | ||||
| 34 | dA4 | 55 nt | 16925.9 | 16924.7 |
| G-quadruplex | ||||
| 35 | dG2 | 20 nt | 6371.1 | 6371.4 |
| 36 | dG1 | 20 nt | 6370.1 | 6370.1 |
| J9a-4-way junction | ||||
| 37 | dG2 | 36 nt | 11038.0 | 11038.2 |
| 38 | dG1 | 36 nt | 11037.0 | 11037.4 |
aSequence details and identifier number, b dA, dC, dG, dT denote nucleotide type, c length in nucleotides (nt), d Purified oligonucleotides were characterized by mass spectrometry on a Finnigan LCQ Advantage MAX ion trap instrumentation connected to an Amersham Ettan micro LC system (negative-ion mode with a potential of −4 kV applied to the spray needle). LC: Sample (250 pmol of oligonucleotide dissolved in 20 μl of 20 mM EDTA solution; average injection volume: 10–20 μl); column (Amersham μRPC C2/C18; 2.1 × 100 mm) at 21°C; flow rate: 100 μl min−1; eluant A: 8.6 mM TEA, 100 mM 1,1,1,3,3,3-hexafluoro-2-propanol in H2O (pH 8.0); eluant B: methanol; gradient: 0–100% B in A within 30 min; UV detection at 254 nm.