Figure 7. Structural distribution of residues in the β₂ and β_3a strands of FKBP51 that exhibit reductions in R₂ values resulting from the L119P substitution.

Residues for which the ¹⁵N R₂ value decreases by more than 0.5 s⁻¹ at 900 MHz ¹H are coloured yellow. There are no other differences in R₂ greater than 0.5 s⁻¹ outside the β₄–β₅ loop. A kink in the β_3a strand occurs at Phe⁶⁷ and Asp⁶⁸ where the amide hydrogen of Asp⁶⁸ is slightly too far from the carbonyl oxygen of Gly⁵⁹ to form a canonical antiparallel β-sheet hydrogen-bonding interaction. This kink occurs at the site of direct contact with the tip of the β₄–β₅ loop as indicated by Lys¹²¹.