Figure 2 |. Crystal structure of sKLB bound to FGF21_CT reveal two distinct binding sites.

a, The structure of sKLB (green) in complex with FGF21_CT (salmon) is shown as ribbon and ball-and-stick representation. N-linked glycans are shown as yellow sticks. Nb914 is omitted for clarity. Regions that do not exhibit significant electron densities are shown as grey dashed lines. b, FGF21_CT binding site showing |F_o|-|F_c| omit map contoured at 3.0 σ for FGF21_CT. c, Surface of sKLB interacting with FGF21_CT are color-coded according to the B-factor values, ranging from 52.76 Ų (blue) to 103.63 Ų (red). d, Surface representation of sKLB (green) highlighting two binding sites, site 1 and site 2 of FGF21_CT (salmon, ball-and-stick). e, Site 1 forms a series of internal hydrogen bonds (black dashed lines) through three consecutive turns (orange, yellow, and light blue), creating a structural element that binds to D1 of sKLB. f, Site 2 interacts with pseudo-substrate binding region of D2 of sKLB.