Table 1.
Distribution of Helicobacter pylori AdSS between dimeric and monomeric forms, sedimentation coefficients, and molecular masses of these forms, obtained from the analytical ultracentrifugation studies of the apo enzyme, its binary complex with IMP and ternary complex with IMP and hadacidin.
| Number of experiments | Detection | Monomer |
Dimer |
|||||
|---|---|---|---|---|---|---|---|---|
| s0w,20 [S] | MWa [kDa] | c(s) [%] | s0w,20 [S] | MWa [kDa] | c(s) [%] | |||
| pH 6.8, 4 °C and 20 °Cb | ||||||||
| AdSS (4.4 or 14.9 µM) | 4(7a) | A280 nm | 3.35–3.70 | 44.1 ± 1.8 | 2.0–16.9 | 5.27–5.82 | 88.0 ± 2.0 | 83.1–98.0 |
| AdSS (5.1 µM) | 1 | Interference | 3.73 | 61.1 | 8.7 | 5.70 | 115.5 | 91.3 |
| AdSS (4.4 or 14.9 µM) IMP (0.1 mM) |
3 | A280 nm | 3.10–3.82 | 42.8 ± 5.0 | 2.8–3.4 | 5.75–5.91 | 92.4 ± 3.8 | 96.6–97.2 |
| AdSS (4.4 or 14.9 µM) IMP (0.1 mM) Hadacidin (1 mM) |
3 | A280 nm | 2.70–3.53 | 35.0 ± 3.9 | 3.4–5.7 | 5.75–5.91 | 89.4 ± 0.7 | 94.3–96.6 |
| pH 9.1, 4 °Cc | ||||||||
| AdSS (5.0 µM) | 1 | A280 nm | 3.41 | 45.3 | 28.7 | 5.57 | 94.5 | 71.3 |
| AdSS (13.4 µM) | 1 | A280 nm | 3.54 | 49.0 | 28.0 | 5.45 | 93.8 | 72.0 |
| AdSS (22.1 µM) | 1 | A280 nm | 3.59 | 48.6 | 29.1 | 5.27 | 86.7 | 70.9 |
The sedimentation velocity method and absorbance at 280 nm and/or interference detection were used.
a
To determine MW of the apo enzyme results in TRIS–HCl pH 9.1, 4 °C were also included.
b
Experiments at 20 mM HEPES-NaOH pH 6.8 + 1 mM TCEP, enzyme activity 1.19 ± 0.10 U/mg.
c
Experiments at 50 mM TRIS–HCl pH 9.1 (at 4 °C) + 2 mM EDTA +1 mM DTT, enzyme activity 0.75 U/mg.