FIGURE 2.
The hydrophobic packing interactions between the β4-β5 loop and the β2+β3a strands in the wild type and K121G variant of the FK1 domain of FKBP51. A, the packing interactions between Ile-122 and Pro-123 of the β4-β5 loop, Leu-61 of the β2 strand, and Phe-67 of the β3a strand are conserved among FKBP51 and FKBP52 as well as among FKBP12 and FKBP12.6 family members as illustrated in the high resolution structures of FKBP51 (yellow, PDB code 3O5Q (22)). These packing interactions are closely maintained in the 1.24-Å resolution structure of the K121G variant (green, PDB code 4R0X). B, the 2Fo − Fc electron density contour map for the K121G variant is displayed at the 1σ level.