Sandbox Reserved 1096: Difference between revisions
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==='''Primary, secondary and tertiary structure'''=== | ==='''Primary, secondary and tertiary structure'''=== | ||
==='''Calcium binding sites and active site'''=== | ==='''Calcium binding sites and active site'''=== | ||
*Stable head to tail dimer | |||
*Monomer comprised of 2 immunoglobulin-like domains + C-term catalytic domain calcium binding site C2-5 are unoccupied in apoPAD2 but electron density on C1 and C6 so those are occupied. | |||
*Same fold as apoenzyme except C3-5 are occupied even though just one site unoccupied, the structure is not catalytically competent, it is explained because the active site nucleophile C647, is just 12 angstrom away from the catalytic center. | |||
*Yet, the 3 other key catalytic residues, D351, H471, D473 are properly positioned to promote catalysis and since they have the same conformation in both the apoenzyme and the holoenzyme, the complex structure PAD2+/Ca2+ represent an intermediaire between the 2 structures. | |||
*This intermediaire structure is stabilized thanks to hydrogen bonds between R347 and Q350 who are in the active site. It also inhibits the movement of C647 who is in the substrate binding pocket. | |||
==='''Catalysis of deimination'''=== | ==='''Catalysis of deimination'''=== | ||
