title: Substrate recognition reduces side-chain flexibility for conserved hydrophobic residues in human Pin1.
abstract: Pin1 is a peptidyl-prolyl isomerase consisting of a WW domain and a catalytic isomerase (PPIase) domain connected by a flexible linker. Pin1 recognizes phospho-Ser/Thr-Pro motifs in cell-signaling proteins, and is both a cancer and an Alzheimer's disease target. Here, we provide novel insight into the functional motions underlying Pin1 substrate interaction using nuclear magnetic resonance deuterium ((2)D) and carbon ((13)C) spin relaxation. Specifically, we compare Pin1 side-chain motions in the presence and absence of a known phosphopeptide substrate derived from the mitotic phosphatase Cdc25. Substrate interaction alters Pin1 side-chain motions on both the microsecond-millisecond (mus-ms) and picosecond-nanosecond (ps-ns) timescales. Alterations include loss of ps-ns flexibility along an internal conduit of hydrophobic residues connecting the catalytic site with the interdomain interface. These residues are conserved among Pin1 homologs; hence, their dynamics are likely important for the Pin1 mechanism.
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Namanja
authors.forename: Tao
authors.initials: T
authors.lastname: Peng
authors.forename: John S
authors.initials: JS
authors.lastname: Zintsmaster
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Elson
authors.forename: Maria G
authors.initials: MG
authors.lastname: Shakour
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Peng
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; C000606846:PIN1 protein, human; D019696:Peptidylprolyl Isomerase