Sandbox Reserved 1096: Difference between revisions
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==Structural Features== | ==Structural Features== | ||
==='''Primary, secondary and tertiary structure'''=== | ==='''Primary, secondary and tertiary structure'''=== | ||
In terms of primary structure, the '''''apoenzyme''''' described under PDB's [https://www.rcsb.org/structure/4N20 4N20] contains 4 key catalytic residues that are essential for citrullination in the active site (C647, D351, H471 and D473). The cysteine residue is involved in nucleophilic attacks that promote deimination of Arginine residues whereas the other residues are mainly responsible for stabilization of substrates entering the active site<ref name="ART1" />. Other key residues may include D125, D127, E131 and E354 which may play an important role in Calcium binding for sites Ca1 and Ca2. In the other hand, the structure of '''''apoPAD2''''' shows some common secondary motifs such as superimposed anti-parallel beta sheets that generate beta sandiwiches. Closer to the C-terminal, both alpha and beta secondary structures may be observed with 17 alpha helixes and multiple parallel and anti-parallel beta sheets that make up an alpha/beta propeller<ref name="ART1" />. Tertiary structure of '''''apoPAD2''''' monomer is well described by [https://pubs.acs.org/doi/10.1021/cb500933j Slade et al.] as being composed of three distinct domains: 2 immunoglobin-like domains (IgG1 and IgG2) at positions (1-115)(116-295) respectively and a C-terminal catalytic domain at (296-665) that contains the active site. Both immunoglobin-like domains comprise typical beta-sandwiches and the catalytic domain generates an alpha/beta propeller. Finally, with respect to the quaternary structure, PAD2 '''''apoPAD2''''' | |||
==='''Calcium binding sites and active site'''=== | ==='''Calcium binding sites and active site'''=== | ||
