TABLE 1.
Affinities of γC toward immobilized IL-21Rα saturated by either wt IL-21 or variants as determined by BIAcore analysis
Four variants (Q116A, I14D, Q116D, and I119D) resulted in very low affinities, which could not be measured in this experiment, and were thus marked as unmeasurable (u.m). All of the variants were measured three times. The relative affinities of IL-21 variants to γC is presented by the KDmut/wt value. mut, IL-21 variants.
| Alanine variant | KD ± S.D. | KDmut/wt | Charge variant | KD ± S.D. | KDmut/wt |
|---|---|---|---|---|---|
| nm | nm | ||||
| M7A | 166 ± 15 | 2.4 | M7D | 382 ± 40 | 5.6 |
| R11A | 264 ± 20 | 3.9 | R11D | 1063 ± 152 | 15.6 |
| I14A | 203 ± 12 | 3.0 | I14D | u.m | u.m |
| D18A | 37 ± 5 | 0.5 | D18K | 57 ± 3 | 0.8 |
| E100A | 137 ± 12 | 2.0 | E100R | 230 ± 13 | 3.4 |
| E109A | 95 ± 15 | 1.4 | E109R | 107 ± 16 | 1.6 |
| S113A | 59 ± 3 | 0.9 | S113D | 396 ± 54 | 5.8 |
| Q116A | u.m | u.m | Q116D | u.m | u.m |
| K117A | 30 ± 4 | 0.4 | K117D | 1091 ± 147 | 16.0 |
| I119A | 187 ± 32 | 2.8 | I119D | u.m | u.m |
| H120A | 142 ± 23 | 2.1 | H120D | 2510 ± 480 | 36.9 |
| L123A | 561 ± 52 | 8.3 | L123D | 3100 ± 236 | 45.6 |
| WT | 68 ± 2 | 1.0 |