TABLE 1.
Stability constants of CD binding to CymA as derived from titration experiments similar to that shown in Fig. 2, using Lineweaver-Burke plots (Fig. 3)
| Sugar | Maltoporin E. coli | CymA K. oxytoca pH 6 | Saturation | pH 5 | pH 8 | T = 6°C |
|---|---|---|---|---|---|---|
| α-cyclodextrin | N.D. | 32,000 | 82% | 16,970 | 28,610 | 84,750 |
| β-cyclodextrin | N.D. | 1970 | 82% | N.D. | N.D. | N.D. |
| γ-cyclodextrin | N.D. | 310 | 94% | N.D. | N.D. | N.D. |
| Maltotriose | 2800 | 20 | 85% | N.D. | N.D. | N.D. |
| Maltopentaose | 14,000 | 75 | 85% | N.D. | N.D. | N.D. |
| Maltoheptaose | 17,000 | 91 | 88% | N.D. | N.D. | N.D. |
The membranes were formed of diphytanoyl phosphatidylcholine dissolved in n-decane. The aqueous solutions were unbuffered and had a pH of 6 unless otherwise indicated. The applied voltage was 20 mV and the temperature was 20°C unless otherwise indicated. The data represent the means of at least three individual titration experiments. The standard deviation was typically <10% of the mean value.