TABLE 3

Comparison of Cu(II) and Zn(II) in complex with bipyridine and Cu(II) in complex with phenanthrolene in respect of residues potentially involved in metal site or as second site interaction

The effect of the metal chelator complexes were measured by the phosphatidyl inositol turnover experiments in transiently transfected COS-7 cells. n refers to the number of experiments. ± values are S.E.M.




Cu(II)-Bipyridine

Zn(II)-Bipyridine

Cu(II)-Phenanthroline


EC50
Kd
n
Fdec.
EC50
Kd
n
Fdec.
EC50
Kd
n
Fdec.
μM -fold μM -fold nM -fold
III:05 G128H -4.7 ± 0.11 22 18 1.0 -4.3 ± 0.08 53 15 1.0 -4.7 ± 0.05 21 8 1.0
Background
III:08 F131A -2.8 ± 0.09 1415a 4 64 -3.0 ± 0.15 971a 6 18 -3.0 ± 0.13 989a 6 47
IV:20 D186N -3.1 ± 0.43 885a 8 40 -2.9 ± 0.31 1240a 4 24 -3.6 ± 0.14 241a 4 12
V:01; V:05 R208A;R212A -4.9 ± 0.04 12 4 0.55 -4.5 ± 0.08 29 3 0.55 -5.1 ± 0.15 7.9 3 0.38
VI:13 W268A -4.3 ± 0.08 50 5 2.3 -3.7 ± 0.24 190 4 3.6 -4.5 ± 0.08 33 6 1.6
VI:16 Y271A -3.1 ± 0.21 812a 4 37 -2.9 ± 0.27 1278a 3 24 -3.4 ± 0.02 433a 3 21
VI:23 D278N -4.3 ± 0.12 55 6 2.5 -3.7 ± 0.16 212 3 4.0 -4.5 ± 0.04 35 4 1.7
VII:02 K300A -4.7 ± 0.09 20 4 0.90 -4.3 ± 0.07 45 3 0.86 -5.1 ± 0.07 7.8 3 0.37
VII:10
Y308A
-3.2 ± 0.45
651a
3
29
-3.2 ± 0.70
568a
3
11
-3.4 ± 0.07
400a
3
19
  • Fdec, decrease in potency for each ligand on a given mutation compared with His III:05-CXCR3 (background).

  • a The EC50 was estimated by a nonlinear regression using the sigmoidal dose-response algorithm in GraphPad Prism with a constant Hill coefficient of 1.5 corresponding to the Hill coefficient of the metal ion chelator complexes on His III:05 CXCR3.