Table 3.
Color properties and active site architecture of wild-type and mutants of GKL.
| Mutation (reconstitution) | Absorbance maximum (nm) / Molar Extinction Coefficient (M−1. cm−1) | Color | β3-loop | Distance (Å) | Occupancy | |||
|---|---|---|---|---|---|---|---|---|
| α - β | Y99 - α | Y99 - β | α | β | ||||
| Wild-type GKL (Fe3+-Zn2+) | 545 / 337 | Purple | ordered | 3.6 (Fe-Zn) | 6.2 | 4.6 | 1.0 | 1.0 |
| E101G / R230C (Fe3+-Zn2+) | 512 / 376 | Purple | disordered | 3.4 (Fe-Zn) | 6.6 | 5.4 | 1.0 | 0.6 |
| E101G / R230C / D266N (Fe3+-Zn2+) + C4-HSL | N.D. | Purple | disordered | 3.6 (Fe-Zn) | 7.2 | 5.6 | 1.0 | 0.7 |
| E101N (Fe3+-Zn2+) | 535 / 435 | Dark Brown | disordered | 3.6 (Fe-Zn) | 6.7 | 5.2 | 1.0 | 0.9 |
| E101N (Fe3+-Mn2+) | 531 / 733 | Dark Brown | ordered | 3.2 (Fe-Mn) | 4.8 | 2.9 | 1.0 | 1.0 |
| E101N / D266N (Fe3+-Mn2+) + C4-HSL | N.D. | Dark Brown | disordered | 3.5 (Fe-Mn) | 7.9 | 6.2 | 0.9 | 0.5 |
| R230D (Fe3+-Zn2+) | 553 / 1066 | Dark Purple | ordered | 3.4 (Fe-Zn) | 5.0 | 3.5 | 1.0 | 0.8 |
α: α-cation; β: β-cation; N.D.: not determined