Table 1.
Summary of comparative data on wild-type versus mutant CblAs.1
| Wild type CblA |
Q273A CblA |
G274S CblA |
K276A CblA |
K276E CblA |
G278D CblA | |
|---|---|---|---|---|---|---|
| Complex distribution + GMPPNP | Higher order oligomers, M2C1 | Higher order oligomers, M2C1 | Higher order oligomers, M2C1 | Higher order oligomers, M2C1 | Higher order oligomers, M2C1 | Higher order oligomers, M2C1 |
| Complex distribution + GDP2 | M2C1, free MCM | M2C1, free MCM | Higher order oligomers, M2C1, free MCM | M2C1, M1C1, free MCM | M2C1, free MCM | free MCM |
| Complex distribution + GTP, after 30 min2 | M2C1, M1C1, free MCM | Higher order oligomers, M2C1 | Higher order oligomers, M2C1 | M2C1, M2C1 free MCM | Higher order oligomers, M2C1 free MCM | M2C1, freeMCM |
| 2GTPaseactivity (min−1) | 0.06 ± 0.04 | 0.03 ± 0.02 | 0.03 ± 0.02 | 0.04 ± 0.02 | 0.03 ± 0.02 | 0.06 ± 0.04 |
| 2GTPase activity + MCM (min−1) | 2.78 ± 0.41 | 0.86 ± 0.22 | 1.04 ± 0.16 | 2.98 ± 0.17 | 0.92 ± 0.09 | 3.07 ± 0.11 |
| 2Kact [μM] | 0.3 ± 0.1 | 10.0 ± 0.4 | 1.7± 0.3 | 5.0 ± 0.3 | 3.8 ± 0.2 | 3.9 ± 0.3 |
| AdoCbl transfer from ATR to MCM + GDP | complete | complete | partial | complete | complete | complete |
| AdoCbl transfer from ATR to MCM + GMPPCP | blocked | blocked | blocked | partial | partial | partial |
| Cob(II)alamin transfer from MCM to ATR + GTP | complete | impaired | almost complete | impaired | impaired | impaired |
1
Differences between wild-type and mutant CblA are highlighted in italics; the dominant oligomeric states are highlighted in bold lettering. 2Kact denotes the concentration of MCM needed for half maximal GTPase activity of CblA. The data represent the mean ± SD of three independent experiments.