TABLE 1.
Affinity for TNP-8N3-ATP of SR and expressed wild type Ca2+-ATPase and mutants in various stabilized states
K0.5 values for photolabeling derived from Figs. 2, 7, and supplemental Fig. S6 are indicated relative (in %) to that of the expressed wild type under the same conditions (for wild type the absolute K0.5 value is shown). The S.E. is indicated with the number of experiments in parentheses.
| EDTAa |
EGTA/Mg2+b | |||||
|---|---|---|---|---|---|---|
| E2 (Tg) | E2·Pi (MgF) | E2·P (vanadate) | E2·P (AlF) | E2−P (BeF) | E1 | |
| Wild type | 100 ± 14 (n = 4) (62 nm) | 100 ± 12 (n = 6) (10.5 nm) | 100 ± 10 (n = 8) (9.6 nm) | 100 ± 9 (n = 9) (11.6 nm) | 100 ± 14 (n = 7) (54 nm) | 100 ± 18 (n = 5) (290 nm) |
| SR | 84 ± 11 (n = 3) | 90 ± 14 (n = 5) | 74 ± 7 (n = 4) | 69 ± 10 (n = 3) | 83 ± 6 (n = 3) | 89 |
| R174A | 331 ± 17 (n = 2) | 269 ± 7 (n = 2) | 251 ± 7 (n = 2) | 255 ± 7 (n = 2) | 795 ± 27 (n = 2) | 73 |
| R174E | 536 ± 43 (n = 2) | 1781 ± 171 (n = 2) | 1735 ± 0 (n = 2) | 878 ± 49 (n = 2) | 1582 ± 340 (n = 2) | 80 |
| I188A | 127 ± 1 (n = 2) | 109 ± 20 (n = 2) | 100 ± 16 (n = 2) | 122 ± 18 (n = 2) | 64 ± 18 (n = 2) | 42 |
| I188F | 87 ± 5 (n = 2) | 154 ± 16 (n = 2) | 76 ± 5 (n = 2) | 69 ± 6 (n = 2) | 19 ± 2 (n = 2) | 68 |
| K205A | 357 ± 2 (n = 2) | 854 ± 196 (n = 2) | 1131 ± 123 (n = 2) | 1031 ± 9 (n = 2) | 567 ± 6 (n = 2) | 56 |
| E439A | 141 ± 6 (n = 2) | 110 ± 6 (n = 2) | 123 ± 11 (n = 2) | 177 ± 11 (n = 3) | 22 ± 3 (n = 2) | 35 |
| F487L | 36 ± 5 (n = 2) | 52 ± 15 (n = 2) | 48 ± 5 n = 2) | 60 ± 0 (n = 2) | 19 ± 0 (n = 2) | 43 |
| F487S | 90 ± 16 (n = 2) | 89 ± 15 (n = 3) | 101 ± 1 (n = 2) | 81 ± 1 (n = 2) | 88 ± 1 (n = 2) | 25 |
| R489L | 965 ± 107 (n = 3) | 116 ± 12 (n = 2) | 108 ± 3 (n = 2) | 120 ± 2 (n = 2) | 702 ± 109 (n = 2) | 85 |
| K492L | No labeling | No labeling | No labeling | No labeling | No labeling | No labeling |
| R560L | 311 ± 0 (n = 2) | 77 ± 19 (n = 2) | 98 ± 16 (n = 3) | 64 ± 8 (n = 2) | 138 ± 5 (n = 2) | 1250 |
| L562F | 136 ± 17 (n = 2) | 100 ± 4 (n = 2) | 81 ± 15 (n = 2) | 110 ± 20 (n = 2) | 52 ± 8 (n = 2) | 25 |
| 4Gi-46/47 | 151 ± 23 (n = 2) | 83 ± 0 (n = 2) | 96 ± 5 (n = 2) | 106 ± 2 (n = 2) | 83 ± 7 (n = 2) | 96 ± 17 (n = 2) |
a EDTA refers to the condition without free Mg2+ present described under “Experimental Procedures.”