Table 4.
Amino acid transport activities in Anabaena sp. strains PCC 7120 and CSS4. BG11C and BG110C-grown filaments were used in 10-min transport assays with 10 μM [14C]amino acid substrate as described in the Experimental Section. Activities are presented in nmol (mg Chl)-1 per 10 min; the mean ± standard deviation of the mean (SE) from the number of measurements indicated in parenthesis is presented. The percentage of the wild-type activities is also given for the mutant. Differences between the mutant and wild-type activities were assessed by the Student’s t test (P indicated in each case).
| Substrate | Transport activity (nmol [mg Chl]−1) | |||||
|---|---|---|---|---|---|---|
| BG11C | BG110C | |||||
| PCC 7120 | CSS4 (alr1519) | PCC 7120 | CSS4 (alr1519) | |||
| Mean ± SE (n) | Mean ± SE (n) | % (P) | Mean ± SE (n) | Mean ± SE (n) | % (P) | |
| Basic | ||||||
| l-Arg | 116 ± 7.64 (3) | 113 ± 3.16 (2) | 98% (0.864) | 187 ± 8.96 (3) | 167 ± 3.58 (2) | 89% (0.327) |
| Acidic | ||||||
| l-Asp | 30.3 ± 1.03 (4) | 42.0 ± 3.85 (2) | 139% (0.214) | 62.1 ± 0.98 (4) | 77.6 ± 3.57 (3) | 125% (0.119) |
| l-Glu | 10.4 ± 1.48 (4) | 10.3 ± 0.64 (3) | 99% (0.970) | 34.7 ± 1.63 (4) | 32.2 ± 1.90 (3) | 93% (0.619) |
| Neutral polar | ||||||
| l-Gln | 118 ± 4.46 (3) | 125 ± 2.15 (2) | 106% (0.487) | 216 ± 5.30 (3) | 214 ± 2.06 (2) | 99% (0.854) |
| Hydrophobic | ||||||
| l-Ala | 224 ± 12.6 (3) | 215 ± 17.8 (2) | 96% (0.826) | 309 ± 11.7 (3) | 299 ± 14.0 (2) | 108% (0.748) |