. Author manuscript; available in PMC: 2019 Mar 16.

Published in final edited form as: Chembiochem. 2018 Feb 13;19(6):604–612. doi: 10.1002/cbic.201700580

Table 1.

α→β residue design strategy for loop residues in 1–3. ^a

Variant (position)	Backbone Geometry	Acyclic β Replacement	ACPC Replacement
1(R17)	α/γ_R	β³R	[S,S]
1(S18)	α/γ_R	β³S	[S,S]
1(S19)	α/γ_R	β³S	[S,S]
1(G20)	γ_L	βG	[R,R],[S,S]
2(A17)	α_R	β³A	[S,S]
2(D18)	γ_R	β³D	[S,S]
2(G19)	γ_L	βG	[R,R]
3(N17)	α_L	β³N	[R,R]
3(G18)	γ_L	βG	[R,R]

^[a]

Loop 1 residue backbone conformations determined for reported structures of 1 (PDB 4GWT), 2 (PDB 2F21) and 3 (PDB 1ZCN), and β-amino acid replacements used at each sequence position. For sequence position G20 within variant 1, substitutions with both enantiomers of ACPC were evaluated. For variant 1, residues R17, S18 and S19 lie at the boundary between αR and γR regions of the Ramachandran plot. Backbone geometry assigned according to the convention described by Thornton et al.^[25]