Table 1. β-1H Hyperfine Coupling and Geometric Parameters.
|
A (MHz) |
||||||||
|---|---|---|---|---|---|---|---|---|
| RNR β2 variant | Ax | Ay | Az | Aiso (MHz) | Relative abundance | ρC1c | 1Hβ1 θ° from EPRc,e | 1Hβ1 θ° from XRDd,e |
| wild type Y122 1Hβ1a | +59 | +52 | +55 | 56 | 1.00 | 0.387 | 19.0 | 15.8f |
| wild type Y122 1Hβ2b | +2.1 | –5.0 | –4.0 | 2.3 | ||||
| wild type Y122 1Hβ1 (this work) | 11.9 | |||||||
| (3,5)F2Y122 1Hβ1 | +56 | +50 | +52 | 53 | 1.00 | 0.370 | 20.3 | 19.7 |
| (3,5)F2Y122 1Hβ2 | –0.5 | –0.5 | +3 | 1.7 | ||||
| (2,3)F2Y122 1Hβ1 INg | +56 | +53 | +53 | 54.3 | 1.00g | 0.388 | 21.7 | 17.2 |
| (2,3)F2Y122 1Hβ2 IN | +1 | +1 | +2 | 1.3 | ||||
| (2,3,5)F3Y122 1Hβ1 IN | +57 | +51 | +54 | 54 | 0.80 | 0.386 | 21.7 | 14.0 |
| (2,3,5)F3Y122 1Hβ2 IN | +0.5 | +0.5 | +3 | 1.3 | ||||
| (2,3,5)F3Y122 1Hβ1 OUT | +43 | +38 | +38 | 39.7 | 0.20 | 0.357 | 34.1 | 29.9 |
| (2,3,5)F3Y122 1Hβ2 OUT | –0.5 | –0.5 | +2 | 0.3 | ||||
| (2,3,6)F3Y122 1Hβ1 IN | +52 | +50 | +56 | 53 | 0.25 | 0.372 | 20.3 | 20.1 |
| (2,3,6)F3Y122 1Hβ2 IN | +1 | +1 | +3 | 1.7 | ||||
| (2,3,6)F3Y122 1Hβ1 OUT | +48 | +44 | +44 | 45.3 | 0.75 | 0.360 | 28.2 | 21.6 |
| (2,3,6)F3Y122 1Hβ2 OUT | –0.5 | +0.5 | +0.3 | 0.1 | ||||
a
HFI parameters from Hogbom et al.78
b
HFI parameters from Hoganson et al.84
c
Computed using TRSSA with B″ = 162 MHz (Svistunenko et al.).85
d
X-ray diffraction (XRD) angles measured manually in PyMOL after addition of hydrogen atoms.
e
The IN and OUT conformations differ by an approximate 180° rotation of the tyrosine ring about Cβ–Cα; here we report the reduced angles (e.g., for θ > 180°, subtract 180°).
f
From PDB 1MXR.78
g
No signal attributable to the OUT conformation was observed.