title: Ligand binding to the PDZ domains of postsynaptic density protein 95.
abstract: Cellular scaffolding and signalling is generally governed by multidomain proteins, where each domain has a particular function. Postsynaptic density protein 95 (PSD-95) is involved in synapse formation and is a typical example of such a multidomain protein. Protein-protein interactions of PSD-95 are well studied and include the following three protein ligands: (i)N-methyl-d-aspartate-type ionotropic glutamate receptor subunit GluN2B, (ii) neuronal nitric oxide synthase and (iii) cysteine-rich protein (CRIPT), all of which bind to one or more of the three PDZ domains in PSD-95. While interactions for individual PDZ domains of PSD-95 have been well studied, less is known about the influence of neighbouring domains on the function of the respective individual domain. We therefore performed a systematic study on the ligand-binding kinetics of PSD-95 using constructs of different size for PSD-95 and its ligands. Regarding the canonical peptide-binding pocket and relatively short peptides (up to 15-mer), the PDZ domains in PSD-95 by and large work as individual binding modules. However, in agreement with previous studies, residues outside of the canonical binding pocket modulate the affinity of the ligands. In particular, the dissociation of the 101 amino acid CRIPT from PSD-95 is slowed down at least 10-fold for full-length PSD-95 when compared with the individual PDZ3 domain.
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, BMC Box 582, Uppsala SE-75123, Sweden Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" Sapienza, Istituto Pasteur-Fondazione Cenci Bolognetti and Istituto di Biologia e Patologia Molecolari del CNR, University of Rome, Rome 00185, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Toto
authors.affiliation: Department of Drug Design and Pharmacology, Center for Biopharmaceuticals, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark.
authors.forename: Søren W
authors.initials: SW
authors.lastname: Pedersen
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, BMC Box 582, Uppsala SE-75123, Sweden.
authors.forename: O Andreas
authors.initials: OA
authors.lastname: Karlsson
authors.affiliation: Department of Drug Design and Pharmacology, Center for Biopharmaceuticals, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark.
authors.forename: Griffin E
authors.initials: GE
authors.lastname: Moran
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, BMC Box 582, Uppsala SE-75123, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Andersson
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, BMC Box 582, Uppsala SE-75123, Sweden.
authors.forename: Celestine N
authors.initials: CN
authors.lastname: Chi
authors.affiliation: Department of Drug Design and Pharmacology, Center for Biopharmaceuticals, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Strømgaard
authors.affiliation: Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" Sapienza, Istituto Pasteur-Fondazione Cenci Bolognetti and Istituto di Biologia e Patologia Molecolari del CNR, University of Rome, Rome 00185, Italy Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK stefano.gianni@uniroma1.it per.jemth@imbim.uu.se.
authors.forename: Stefano
authors.initials: S
authors.lastname: Gianni
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, BMC Box 582, Uppsala SE-75123, Sweden stefano.gianni@uniroma1.it per.jemth@imbim.uu.se.
authors.forename: Per
authors.initials: P
authors.lastname: Jemth
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D054731:PDZ Domains; D011485:Protein Binding; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C112203:CRIPT protein, human; D008024:Ligands; C121001:NR2B NMDA receptor; D009419:Nerve Tissue Proteins; D016194:Receptors, N-Methyl-D-Aspartate; C033652:postsynaptic density proteins; D052248:Nitric Oxide Synthase Type I
keywords: CRIPT; GluN2B; Kinetics; PDZ domain; PSD-95