Table III. (Rp)-cAMPS effects on amide H/2H exchange in RIα(91–244) complexed to the C-subunit.
Non-overlapping 95% confidence intervals relative to control values were determined by the PrizmTM computer program.
| Fragment of R-subunit (m/z) (region) | Number of exchangeable amides | Charge (z) | Maximum amides exchanged (mean ± S.E.)a |
|
|---|---|---|---|---|
| Control | Plus (Rp)-cAMPS | |||
| 102–106 (640.29) (linker) | 4 | 1 | 3.0 ± 0.01 | 2.9 ± 0.07 |
| 111–126 (632.70) (linker) | 14 | 3 | 8.7 ± 0.26 | 9.0 ± 0.34 |
| 112–119 (477.81) (linker) | 6 | 2 | 4.2 ± 0.09 | 4.6 ± 0.13 |
| 126–134 (493.29) (αXn) | 8 | 2 | 3.4 ± 0.05 | 3.6 ± 0.10 |
| 136–143 (976.40) (loop-αA) | 7 | 1 | 1.8 ± 0.12 | 2.4 ± 0.14 |
| 136–148 (797.86) (loop-αA) | 12 | 2 | 1.3 ± 0.08 | 1.7 ± 0.10 |
| 144–148 (637.34) (αA) | 4 | 1 | 0.3 ± 0.24 | 0.1 ± 0.02 |
| 149–156 (913.42) (αA) | 6 | 1 | 1.2 ± 0.03 | 1.2 ± 0.23 |
| 157–172 (846.89) (β2-β3) | 15 | 2 | 5.7 ± 0.18 | 4.8 ± 0.22 |
| 161–172 (1322.58) (β2-β3) | 11 | 1 | 4.8 ± 0.17 | 3.9 ± 0.21 |
| 162–172 (1225.54) (β2-β3) | 10 | 1 | 4.7 ± 0.16 | 3.9 ± 0.20 |
| 172–180 (1101.49) (β4) | 8 | 1 | 1.1 ± 0.02 | 1.1 ± 0.04 |
| 183–187 (638.28) (β4) | 4 | 1 | 2.0 ± 0.02 | 2.0 ± 0.04 |
| 188–198 (1097.49) (β5-β6) | 10 | 1 | 4.0 ± 0.10 | 4.0 ± 0.15 |
| 188–201(1396.64) (β5-β6-αB′) | 13 | 1 | 6.4 ± 0.22 | 4.5 ± 0.16 |
| 202–212 (567.32) (αB′) | 9 | 2 | 3.7 ± 0.14 | 1.9 ± 0.18 |
| 202–221 (705.76) (αB′-β7) | 18 | 3 | 4.1 ± 0.18 | 2.4 ± 0.14 |
| 204–221(644.3) (αB′-β7) | 16 | 3 | 4.0 ± 0.13 | 2.0 ± 0.14 |
| 213–221 (500.83) (β7) | 8 | 2 | 0.8 ± 0.01 | 1.0 ± 0.03 |
| 222–229 (506.23) (β8-αB) | 6 | 2 | 0.6 ± 0.05 | 0.6 ± 0.07 |
| 230–238 (523.81) (αB-αC) | 8 | 2 | 2.6 ± 0.05 | 2.6 ± 0.11 |
a Average number of deuterons exchanged determined from fitting plots of the time course of deuteration during a 10-min exposure to deuterium oxide to a single exponential equation. Values reported are the mean and S.E. of the amplitude term of fits, and results are from at least two independent experiments. Peptides showing significant differences upon (Rp)-cAMPS binding are in bold. All deuterium exchange values reported were corrected for a 32.7% back-exchange by multiplying the raw centroid values by a multiplication factor of 1.49.