TABLE 1.
Ca2+ dissociation kinetics of CaM and mutant CaMs
The mean dissociation rate constants (koff) and the standard deviation are shown for each EF hand in wild type CaM, CaM12, and CaM34, respectively; n refers to the number of independent experiments from which the data was obtained. The relative amplitude (A) is also shown for each EF hand; this represents the involvement of the particular hand in the binding of Ca2+, with an A of 1 being equal to 100% binding capability. The CaM N-lobe EF hands are represented in the left four columns, and the C-lobe EF hands are represented in the right four columns. A rate constant of 1000 s–1 represents a rate that was too fast to measure.
|
N-terminal CaM lobe
|
C-terminal CaM lobe
|
n
|
|||||||
|---|---|---|---|---|---|---|---|---|---|
|
EF1a
|
EF2a
|
EF3a
|
EF4a
|
||||||
| k1 | A1 | k2 | A2 | k3 | A3 | k4 | A4 | ||
| s-1 | s-1 | s-1 | s-1 | ||||||
| CaM | 1000 | 1 | 1000 | 1 | 10.9 ± 1.2 | 1 | 10.9 ± 1.2 | 1 | 4 |
| CaM12 | 11.2 ± 0.7 | 1 | 11.2 ± 0.7 | 1 | 4 | ||||
| CaM34 | 1000 | 1 | 190 ± 15 | 1 | 3 | ||||
Note that the denotations given to the EF hands are for reference purposes only and do not correlate to the actual hand involved in the reaction.