Supplementary Figure 10: A20I325N subtly impacts the OTU structure.
From: Denisovan, modern human and mouse TNFAIP3 alleles tune A20 phosphorylation and immunity
(a) Structures of human I325N (orange) and wild-type (WT; grey) A20 OTU domains superposed (each with 6 molecules per asymmetric unit). The dimer partner of one of these is shown in pink. Loop 317 and 280 are indicated on the periphery. (b) The I325N substitution does not alter the fold of the putative catalytic triad (orange cartoon and sticks) compared to previously published wild-type structures (cyan cartoon and sticks; PDB entries 3DKB, 2VFJ and 3ZJD). (c) The fold is additionally unperturbed by acetamidylation of C103 (orange mesh; 2mFo-DFc composite omit map contoured at 1.2 sigma). (d-f) The I325N substituted side-chain sits at the base of the β7-β8 loop containing residue 317, in a pocket also lined by the β6-β9 loop containing residue 280 (d). Adjacent hydrophobic residues include W85, V276, F283, I312, V314 (e). The I325N substitution results in the base of the β7-β8 loop splaying apart (f, arrow), increasing β7-β8 loop disorder. (g) Structures of human I325N (orange) and wild-type (WT; grey) A20 OTU domains superposed on the wild-type OTU-ubiquitin structure 5LRX44. Conserved residues on the posterior surface are coloured orange. The β3-β4 loop containing the C243Y substitution and the structured base of the β7-β8 loop containing the I325N allele marked.
