Table 2. Backrub changes at β aromatics across from Gly vs. other.

Structures	Average Crystal	BRDEE 1gyh A	BRDEE 1khb A	BRDEE 1z84 A
Aromatic	F	Y109	F144	F171
Opposite	G→A	G122→[A]	G157→[A]	Q188→[G]
ΔCα i−1 (Å)	0.01	0.02	0.01	0.01
ΔCα i (Å)	0.28	0.25	0.24	0.20
ΔCα i+1 (Å)	0.09	0.03	0.01	0.02
ΔCβ i (Å)	0.64	0.50	0.51	0.47
ΔCζ i (Å)	1.34	0.96	1.05	1.01
Backrub (°)	−11	−10	−11	−11
Δτ i−1 (°)	−0.2	−0.5	−0.4	+0.3
Δτ i+1 (°)	+1.0	+2.8	+1.5	+1.2

Distances are after superposition into the same reference frame using 5 C_αs (aromatic i−2, i−1, i+1, i+2 and opposite i).

Distances for BRDEE for atoms at or beyond Cα i±1 are shown, as opposed to the N-cap case, because superposition into the same reference frame is subtly affected by allowing backrubs at the opposite C_α in BRDEE.

The signs of the backrub rotation angles and Δτ values are in terms of across-from-Gly→across-from-other.

For average crystal structures, average sidechains (based on average C_β positions and χ dihedral angles) were added in KiNG. The τ value used for each Δτ is an average across the crystal structure ensemble, to be consistent with the methodology for N-caps.

For input to BRDEE, each example was used twice: first with its original deposited sidechain on the opposite strand, and then with a fully ideal sidechain of the opposite type (Gly if originally not Gly, Ala if originally Gly) added in KiNG (residue names in [brackets]). The τ value used for each Δτ is taken directly from the lowest-energy computed structure.