title: Common features in the unfolding and misfolding of PDZ domains and beyond: the modulatory effect of domain swapping and extra-elements.
abstract: PDZ domains are protein-protein interaction modules sharing the same structural arrangement. To discern whether they display common features in their unfolding/misfolding behaviour we have analyzed in this work the unfolding thermodynamics, together with the misfolding kinetics, of the PDZ fold using three archetypical examples: the second and third PDZ domains of the PSD95 protein and the Erbin PDZ domain. Results showed that all domains passed through a common intermediate, which populated upon unfolding, and that this in turn drove the misfolding towards worm-like fibrillar structures. Thus, the unfolding/misfolding behaviour appears to be shared within these domains. We have also analyzed how this landscape can be modified upon the inclusion of extra-elements, as it is in the nNOS PDZ domain, or the organization of swapped species, as happens in the second PDZ domain of the ZO2 protein. Although the intermediates still formed upon thermal unfolding, the misfolding was prevented to varying degrees.
authors.affiliation: Departmento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Murciano-Calles
authors.affiliation: Department de Bioquímica I Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra 08193, Barcelona, Spain.
authors.forename: Jofre
authors.initials: J
authors.lastname: Güell-Bosch
authors.affiliation: Department de Bioquímica I Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra 08193, Barcelona, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Villegas
authors.affiliation: Departmento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain.
authors.forename: Jose C
authors.initials: JC
authors.lastname: Martinez
mesh_terms: D000595:Amino Acid Sequence; D002152:Calorimetry, Differential Scanning; D008958:Models, Molecular; D054731:PDZ Domains; D011487:Protein Conformation; D017510:Protein Folding; D058767:Protein Unfolding; D017550:Spectroscopy, Fourier Transform Infrared