eprintid: 17284 rev_number: 16 userid: 1419 dir: disk0/00/01/72/84 datestamp: 2013-02-13 16:16:18 lastmod: 2019-02-02 15:57:25 status_changed: 2013-02-13 16:16:18 type: article metadata_visibility: show item_issues_count: 0 eprint_status: archive creators_name: Xiong, K creators_name: Zwier, MC creators_name: Myshakina, NS creators_name: Burger, VM creators_name: Asher, SA creators_name: Chong, LT creators_email: creators_email: creators_email: creators_email: creators_email: asher@pitt.edu creators_email: creators_id: creators_id: creators_id: creators_id: creators_id: ASHER creators_id: title: Direct observations of conformational distributions of intrinsically disordered p53 peptides using UV Raman and explicit solvent simulations ispublished: pub divisions: sch_as_chemistry full_text_status: public abstract: We report the first experimental measurements of Ramachandran Ψ-angle distributions for intrinsically disordered peptides: the N-terminal peptide fragment of tumor suppressor p53 and its P27S mutant form. To provide atomically detailed views of the conformational distributions, we performed classical, explicit-solvent molecular dynamics simulations on the microsecond time scale. Upon binding its partner protein, MDM2, wild-type p53 peptide adopts an α-helical conformation. Mutation of Pro27 to serine results in the highest affinity yet observed for MDM2-binding of the p53 peptide. Both UV resonance Raman spectroscopy (UVRR) and simulations reveal that the P27S mutation decreases the extent of PPII helical content and increases the probability for conformations that are similar to the α-helical MDM2-bound conformation. In addition, UVRR measurements were performed on peptides that were isotopically labeled at the Leu26 residue preceding the Pro27 in order to determine the conformational distributions of Leu26 in the wild-type and mutant peptides. The UVRR and simulation results are in quantitative agreement in terms of the change in the population of non-PPII conformations involving Leu26 upon mutation of Pro27 to serine. Finally, our simulations reveal that the MDM2-bound conformation of the peptide is significantly populated in both the wild-type and mutant isolated peptide ensembles in their unbound states, suggesting that MDM2 binding of the p53 peptides may involve conformational selection. © 2011 American Chemical Society. date: 2011-09-01 date_type: published publication: Journal of Physical Chemistry A volume: 115 number: 34 pagerange: 9520 - 9527 refereed: TRUE issn: 1089-5639 id_number: 10.1021/jp112235d other_id: NLM NIHMS293208 other_id: NLM PMC3161171 pmcid: PMC3161171 pmid: 21528875 mesh_headings: Binding Sites mesh_headings: Chemistry, Physical mesh_headings: Computer Simulation mesh_headings: Humans mesh_headings: Leucine--chemistry mesh_headings: Leucine--metabolism mesh_headings: Models, Molecular mesh_headings: Peptide Fragments--chemistry mesh_headings: Peptide Fragments--genetics mesh_headings: Peptide Fragments--metabolism mesh_headings: Proline--chemistry mesh_headings: Proline--metabolism mesh_headings: Protein Binding mesh_headings: Protein Structure, Secondary mesh_headings: Protein Structure, Tertiary mesh_headings: Proto-Oncogene Proteins c-mdm2--chemistry mesh_headings: Proto-Oncogene Proteins c-mdm2--genetics mesh_headings: Proto-Oncogene Proteins c-mdm2--metabolism mesh_headings: Serine--chemistry mesh_headings: Serine--metabolism mesh_headings: Solvents--chemistry mesh_headings: Spectrum Analysis, Raman mesh_headings: Tumor Suppressor Protein p53--chemistry mesh_headings: Tumor Suppressor Protein p53--genetics mesh_headings: Tumor Suppressor Protein p53--metabolism chemical_names: Peptide Fragments chemical_names: Solvents chemical_names: Tumor Suppressor Protein p53 chemical_names: Proline chemical_names: Serine chemical_names: Leucine chemical_names: MDM2 protein, human chemical_names: Proto-Oncogene Proteins c-mdm2 citation: Xiong, K and Zwier, MC and Myshakina, NS and Burger, VM and Asher, SA and Chong, LT (2011) Direct observations of conformational distributions of intrinsically disordered p53 peptides using UV Raman and explicit solvent simulations. Journal of Physical Chemistry A, 115 (34). 9520 - 9527. ISSN 1089-5639 document_url: http://d-scholarship-dev.library.pitt.edu/17284/1/licence.txt