Figure 12.

QTY code for transmembrane protein redesign. (A) Crystallographic electron density maps for amino acids involved in the pairwise substitution of QTY code. Hydrophobic amino acid LIVF are replaced by hydrophilic QTY to stabilize GPCRs in aqueous environment. Reprinted with permission from ref (277). Copyright 2019 National Academy of Sciences. (B) Computer simulations of CCR5^QTY (cyan) and CXCR4^QTY (blue) in explicit water environment (24.85 °C at pH 7.4 and 0.9% NaCl) are superimposed with the crystal structures of CCR5 (PDB ID: 4MBS, magenta) and CXCR4 (PDB ID: 3ODU, green). Two side views and one top view are shown. Reprinted with permission from ref (274). Copyright 2018 National Academy of Sciences. (C) De novo predicted structure superimpositions for CCR5^QTY (cyan) with CCR5 (green) by AlphaFold2. (D) De novo predicted structure superimpositions for CCR2^QTY (cyan) with CCR2 (green) by AlphaFold2.