Fig. 5. Structural analysis of GB1 thioamide variants. Left: Overall structure of GB1 with modeled thioamide substitutions. Each thioamide substitution is poised to make two hydrogen bonding interactions with opposing strands. Right: Zoomed in region showing that the LeuS 7 thiocarbonyl is skewed out of the plane of the anti-parallel β-sheet (C O···N angle = 134°), providing a potential explanation for why it is less destabilizing than LeuS 5 or IleS 6. Structures rendered from PDB entry ; 2QMT. 48 .
