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Figure 2
Overall structure of PAD6. (a) Domain organization of PAD6. The N-terminal IgG1, N-terminal IgG2 and the C-terminal catalytic domains are coloured in cyan, green and blue, respectively. (b) Model of the PAD6 dimer constructed with the symmetry mate of the crystal lattice. Overlay and comparison with the PAD4 dimer and r.m.s.d. calculated from PDB entry 2dew. (c) Analytical size-exclusion chromatography of PAD6 using a Superdex 200 5/150GL column equilibrated with 20 mM Tris pH 7.5, 200 mM NaCl, 1 mM TCEP. The elution volumes for PAD6 and bovine gamma globulin standard (158 kDa) were 1.7 ml for both samples. Inlet: standards in white circles and PAD6 in the black triangle. The molecular weight for PAD6 is estimated at ∼182 kDa. (d) Comparison between interacting residues involving the I-loops of PAD4 (orange) or that of PAD6 (blue). The I-loop is coloured red in PAD4 and purple in PAD6. In PAD6, the I-loop contains a disordered fragment (Pro445–Gly449) represented as a dashed line. The equivalent residues Tyr435 (PAD4) and Tyr444 (PAD6) are indicated with a star. Left panel: an overlay between PAD4 and PAD6 focused on the I-loop, showing different interface interactions involving Tyr435 (PAD4) and Tyr444 (PAD6). Right panels: detailed descriptions of the interactions involving Tyr435 in PAD4 (top) and those involving Tyr444 in PAD6 (bottom).

IUCrJ
Volume 11| Part 3| May 2024| Pages 395-404
ISSN: 2052-2525
https://doi.org/10.1107/S2052252524002549