Table 2.
Affinity of 12G5, FC131, [Cit1]FC131, [Aib1]FC131 and [D-Arg1]FC131 for WT CXCR4 and various CXCR4 mutations
| Receptor | 12G5 | FC131 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Helix | Position | Mutation | IC50 ± SEM (log) | IC50 (nM) | Fmut | Bmax ± SEM (fmol/105 cells) | (n) | P (Bmax) | IC50 ± SEM (log) | IC50 (μM) | Fmut | P | (n) |
| WT | WT | WT | −8.3 ± 0.13 | 4.7 | 1.0 | 0.096 ± 0.018 | (12) | −6.1 ± 0.09 | 0.76 | 1.0 | (12) | ||
| TM-2 | II:20/2.60 | W94A | −8.7 ± 0.15 | 1.9 | 0.40 | 0.053 ± 0.022 | (8) | −7.5 ± 0.07 | 0.03 | 0.04 | *** | (9) | |
| II:23/2.63 | D97A | −8.0 ± 0.12 | 9.4 | 2.0 | 0.086 ± 0.013 | (3) | −6.8 ± 0.15 | 0.17 | 0.22 | ** | (3) | ||
| TM-3 | III:05/3.29 | H113A | −8.6 ± 0.15 | 2.7 | 0.58 | 0.037 ± 0.006 | (7) | * | −4.3 ± 0.18 | 48 | 63 | *** | (8) |
| III:08/3.32 | Y116A | −8.1 ± 0.08 | 8.7 | 1.9 | 0.036 ± 0.016 | (5) | > −4 | >100 | >132 | (3) | |||
| TM-4 | IV:20/4.60 | D171N | −8.7 ± 0.18 | 2.2 | 0.47 | 0.034 ± 0.017 | (7) | * | −4.3 ± 0.12 | 55 | 72 | *** | (8) |
| ECL-2 | ECL-2 / Cys+1 | D187A | −7.8 ± 0.04 | 16 | 3.4 | 0.161 ± 0.012 | (3) | −5.1 ± 0.18 | 7.7 | 10 | *** | (3) | |
| TM-6 | VI:23/6.58 | D262N | −8.4 ± 0.15 | 3.7 | 0.79 | 0.101 ± 0.020 | (8) | −4.1 ± 0.18 | 73 | 96 | *** | (9) | |
| TM-7 | VII:−02/7.32 | H281A | −8.6 ± 0.15 | 2.4 | 0.52 | 0.028 ± 0.008 | (7) | * | −4.9 ± 0.11 | 13 | 18 | *** | (8) |
| VII:06/7.39 | E288A | −8.7 ± 0.16 | 2.1 | 0.45 | 0.035 ± 0.011 | (7) | * | −5.4 ± 0.12 | 4.1 | 5.5 | *** | (8) | |
| Receptor | [Cit1]FC131 | [Aib1]FC131 | [D-Arg1]FC131 | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Helix | Position | Mutation | IC50 ± SEM (log) | IC50 (μM) | Fmut | P | (n) | IC50 ± SEM (log) | IC50 (μM) | Fmut | P | (n) | IC50 ± SEM (log) | IC50 (μM) | Fmut | P | (n) |
| WT | WT | WT | −5.3 ± 0.12 | 4.9 | 1.0 | (11) | −5.5 ± 0.16 | 2.9 | 1.0 | (5) | −6.4 ± 0.14 | 0.38 | 1.0 | (6) | |||
| TM-2 | II:20/2.60 | W94A | −6.6 ± 0.16 | 0.27 | 0.06 | *** | (9) | −6.9 ± 0.33 | 0.14 | 0.05 | ** | (3) | −7.5 ± 0.09 | 0.03 | 0.08 | ** | (3) |
| II:23/2.63 | D97A | −6.1 ± 0.05 | 0.87 | 0.18 | ** | (3) | −5.9 ± 0.09 | 1.2 | 0.40 | ns | (3) | No displacement | (3) | ||||
| TM-3 | III:05/3.29 | H113A | >−4 | >100 | >20 | *** | (8) | No displacement | (3) | No displacement | (3) | ||||||
| III:08/3.32 | Y116A | >−4 | >100 | >20 | *** | (2) | No displacement | (2) | >−4 | >100 | >261 | (3) | |||||
| TM-4 | IV:20/4.60 | D171N | −4.3 ± 0.11 | 47 | 9.6 | *** | (8) | >−4 | >100 | >34 | *** | (3) | >−4 | >100 | >261 | (3) | |
| ECL-2 | ECL-2 / Cys+1 | D187A | −5.4 ± 0.20 | 4.3 | 0.87 | ns | (3) | −5.6 ± 0.19 | 2.6 | 0.9 | ns | (3) | −4.9 ± 0.17 | 12 | 31 | *** | (3) |
| TM-6 | VI:23/6.58 | D262N | −4.2 ± 0.10 | 61 | 12 | *** | (9) | >−4 | >100 | >34 | *** | (3) | >−4 | >100 | >261 | (3) | |
| TM-7 | VII:−02/7.32 | H281A | −4.5 ± 0.17 | 31 | 6.3 | *** | (8) | −4.0 ± 0.10 | 91 | 31 | *** | (3) | −4.0 ± 0.21 | 107 | 280 | *** | (3) |
| VII:06/7.39 | E288A | −5.7 ± 0.19 | 2.1 | 0.44 | ns | (6) | −5.4 ± 0.10 | 4.2 | 1.4 | ns | (3) | >−4 | >100 | >261 | (3) | ||
The data were obtained from competition binding with 125I-labelled antibody 12G5 as radioligand on transiently transfected COS-7 cells. Values in parentheses represent number of experiments (n), and Fmut indicates the fold-difference (ratio) between the affinities on mutant receptor compared with WT receptor with codes as follows: bold >100 or no displacement at all, bold and italic >25, italic >5, underline <0.2. ***P < 0.001, **P < 0.01, *P < 0.05. Residue nomenclature is given in Table 2013.