TABLE 1.
Values of kinetic parameters for CA polymerization in vitro in different conditions, in either the absence or presence of molecular crowding agents
| Variable | pH | [NaCl] (M) | [CA]a (μM) | [Crowder] (g/liter) | t50b (min) | nb | Linear ratec (OD/min) |
|---|---|---|---|---|---|---|---|
| pH | 7.0 | 2.25 | 44 | 0 | 8.7 ± 0.02 | 2.8 ± 0.02 | 0.17 |
| 7.8 | 2.25 | 44 | 0 | 1.3 ± 0.01 | 3.1 ± 0.03 | 1.14 | |
| [NaCl] | 7.8 | 0.15 | 66 | 0 | —d | — | — |
| 7.8 | 0.75 | 15 | 0 | — | — | — | |
| 7.8 | 2.25 | 15 | 0 | 27.8 ± 0.02 | 5.3 ± 0.01 | 0.04 | |
| [CA] | 7.8 | 2.25 | 5 | 0 | — | — | — |
| 7.8 | 2.25 | 10 | 0 | — | — | — | |
| 7.8 | 2.25 | 15 | 0 | 27.8 ± 0.02 | 5.3 ± 0.01 | 0.04 | |
| 7.8 | 2.25 | 22 | 0 | 7.5 ± 0.01 | 4.4 ± 0.01 | 0.18 | |
| 7.8 | 2.25 | 44 | 0 | 1.3 ± 0.01 | 3.1 ± 0.03 | 1.14 | |
| [Crowder] | 7.8 | 2.25 | 15 | 0 | 27.8 ± 0.02 | 5.3 ± 0.01 | 0.04 |
| 7.8 | 2.25 | 15 | 25 Ficoll | 13.1 ± 0.01 | 4.7 ± 0.01 | 0.08 | |
| 7.8 | 2.25 | 15 | 50 Ficoll | 7.1 ± 0.01 | 4.6 ± 0.02 | 0.14 | |
| 7.8 | 2.25 | 15 | 100 Ficoll | 2.3 ± 0.02 | 2.6 ± 0.04 | 0.21 | |
| 7.8 | 2.25 | 15 | 100 dextran | 4.5 ± 0.01 | 3.1 ± 0.02 | 0.12 | |
| Mutation and crowder | |||||||
| High salt | 7.8 | 2.25 | 15 nonmutated | 0 | 27.8 ± 0.02 | 5.3 ± 0.01 | 0.04 |
| 7.8 | 2.25 | 15 mutant | 0 | — | — | — | |
| 7.8 | 2.25 | 15 nonmutated | 100 Ficoll | 2.3 ± 0.02 | 2.6 ± 0.04 | 0.21 | |
| 7.8 | 2.25 | 15 mutant | 100 Ficoll | 11.8 ± 0.02 | 3.2 ± 0.02 | 0.07 | |
| Low salt | 7.8 | 0.15 | 600 nonmutated | 0 | — | — | — |
| 7.8 | 0.15 | 600 mutant | 0 | — | — | — | |
| 7.8 | 0.15 | 600 nonmutated | 250 Ficoll | 1.1 ± 0.2 | 1.9 ± 0.6 | 8.6 | |
| 7.8 | 0.15 | 600 mutant | 250 Ficoll | 2.1 ± 0.4 | 1.7 ± 0.6 | 5.4 |
a
Total CA (monomer) concentration.
b
t50 is the time at which the optical density (OD) is equal to one-half the optical density extrapolated at infinite time and n is the cooperativity parameter. The values given were obtained by fitting the data to equation 1. The fitting errors are indicated.
c
The linear polymerization rate is the average increase in optical density per minute for the approximately linear part of the polymerization curve.
d
—, no significant polymerization observed.