Probing the Roles of Calcium-Binding Sites during the Folding of Human Peptidylarginine Deiminase 4.

ABSTRACT: Our recent studies of peptidylarginine deiminase 4 (PAD4) demonstrate that its non-catalytic Ca²⁺-binding sites play a crucial role in the assembly of the correct geometry of the enzyme. Here, we examined the folding mechanism of PAD4 and the role of Ca²⁺ ions in the folding pathway. Multiple mutations were introduced into the calcium-binding sites, and these mutants were termed the Ca1_site, Ca2_site, Ca3_site, Ca4_site and Ca5_site mutants. Our data indicate that during the unfolding process, the PAD4 dimer first dissociates into monomers, and the monomers then undergo a three-state denaturation process via an intermediate state formation. In addition, Ca²⁺ ions assist in stabilizing the folding intermediate, particularly through binding to the Ca3_site a

SUBMITTER: Liu YL 

PROVIDER: S-EPMC5445078 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature