Figure 6. Common binding epitope identified between the promiscuous shared cytokine receptors.

(A) Superposition of sIL-10R2 (yellow), gp130 (magenta), and γc chain (green). The inset shows the structural similarity of L3 loop residues Y82^sIL-10R2, F169^gp130 (F191^gp130 in uniprot database P40189), and Y103^γc. EPOR and the growth hormone receptor (GHR) also have aromatic L3 residues (F93^EPOR and W104^GHR) which have diverged from the structural alignment shown in Figure 6A (See Figure S7). (B) The position of Y82^sIL-10R2 and F169^gp130 are conserved in their respective ternary complexes. Ribbon diagram of the IL-22TC model (Fig 4) with IL-22/sIL-22R1 colored cyan and sIL-10R2 colored yellow. IL-6 from the IL-6/IL-6R/gp130 complex (pdbid 1P9M, (Boulanger et al., 2003)) was superimposed onto IL-22 from the IL-22TC model (Fig 4) and the position of gp130 (green) is shown. The inset shows IL-22 residues Y51^IL-22, and R55^IL-22 along with Y82^sIL-10R2 (yellow) and F169^gp130 (magenta).