Table 1.
Experimental UV−Vis Absorption, EPR (from Fitted Simulations), and Reduction Potential Data for the T1 and T2 Copper Sites in the NiR Azurin Models in 50 mM Ammonium Acetate pH 5.1a
| variant | T1 Cu: S→Cu CT, nm (ε, M−1 cm−1) |
T2 Cu: peak, nm (ε, M−1 cm−1) |
T1 and T2 Cu: g∥ (A∥(G)), gx (Ax), gy (Ay) | T1/T2 E vs NHE ( ±5 mV) |
|---|---|---|---|---|
| WT azurin | 626 (5000) | T1: 2.260 (55), 2.047 (14), 2.051 (6) | 358/− | |
| Az-NiR | 625 (4850) | 722 (51) | T1: 2.258 (52), 2.048 (9), 2.048 (5) | 350/257 |
| T2: 2.315 (160), 2.068 (7), 2.070 (9) | ||||
| Az-NiR3His | 627 (4700) | 690 (65) | T1: 2.265 (47), 2.047 (12), 2.049 (4) | 359/270 |
| T2: 2.296 (160), 2.059 (2), 2.070 (2) | ||||
| Az-PHM | 627 (5400) | 677 (31) | T1: 2.262 (53), 2.046 (13), 2.051 (9) | 353/251 |
| T2: 2.297 (165), 2.050 (15), 2.074 (7) | ||||
| Az-PHM3His | 627 (5600) | 715 (43) | T1: 2.262 (53), 2.047 (13), 2.049 (2) | 357/258 |
| T2: 2.298 (165), 2.057 (12), 2.071 (11) | ||||
| native NiR | 590 (2300)18,63 | 790 (85)64 | T1: 2.19 (67), 2.06, 2.02 (50)18 | 247/21818,63 |
| T2: 2.31 (150), 2.07, 2.0763 | ||||
| CuSO4 | 764 (24) | 2.366 (142), 2.068 (6), 2.080 (6) | −/213 |