eprintid: 10618 rev_number: 13 userid: 357 dir: disk0/00/01/06/18 datestamp: 2012-01-18 19:34:08 lastmod: 2017-01-18 06:15:03 status_changed: 2012-01-18 19:34:08 type: thesis_degree metadata_visibility: show contact_email: georgelengyel@gmail.com item_issues_count: 0 eprint_status: archive creators_name: Lengyel, George creators_email: gal23@pitt.edu creators_id: GAL23 title: Designing Methodology for the Incorporation of Beta-Amino Acids into Protein Tertiary Structures ispublished: unpub divisions: sch_as_chemistry full_text_status: public keywords: amino acid, peptide, beta, residue, tertiary structure, secondary structure, beta sheet abstract: The goal of this project is to explore methodologies applicable to introducing β-amino acid residues into natural protein sequences with well-defined tertiary structures while maintaining the folded structure of these natural sequences. Hybrid α/β-peptides synthesized with β-amino acids have additional rotational freedom of their backbone and also have increased resistance to proteolysis relative to natural α-peptides. 16 unnatural β-amino acids with varied stereochemistry and torsional restraints were synthesized using a variety of published literature methods. A peptide model system known to fold into a β-hairpin secondary structure in aqueous solution was chosen for substitution with the unnatural residues at two positions. Using Fmoc solid-phase peptide synthesis, 16 hybrid α/β-peptides as well as 16 unfolded control peptides were synthesized and studied by 2D NMR. Using the NMR data obtained from this study, the mutant peptides were analyzed for indications of folded population. Three peptides showed a high degree of folded population: those including a β3 -amino acid and two including the enantiomers of a trans- disubstituted-β2,3 -amino acid. NOE-derived distance restraints were established and high-resolution 3D structures of these peptides were calculated. Using these structures, it was found that the peptide substituted with (2R, 3S)-3-amino-2,4-dimethylpentanoic acid most closely emulated the hairpin structure of the model system. Currently, work is ongoing to determine the effect of side-chain functionalization and substitution pattern on the folding of larger protein systems. date: 2012-01-18 date_type: published pages: 127 institution: University of Pittsburgh refereed: TRUE etdcommittee_type: committee_chair etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_name: Horne, William etdcommittee_name: Nelson, Scott etdcommittee_name: Spence, Megan etdcommittee_email: horne@pitt.edu etdcommittee_email: sgnelson@pitt.edu etdcommittee_email: mspence@pitt.edu etdcommittee_id: HORNE etdcommittee_id: SGNELSON etdcommittee_id: MSPENCE etd_defense_date: 2011-11-11 etd_approval_date: 2012-01-18 etd_submission_date: 2011-12-01 etd_release_date: 2012-01-18 etd_access_restriction: 5_year etd_patent_pending: FALSE assigned_doi: doi:10.5195/pitt.etd.2011.10618 thesis_type: thesis degree: MS citation: Lengyel, George (2012) Designing Methodology for the Incorporation of Beta-Amino Acids into Protein Tertiary Structures. Master's Thesis, University of Pittsburgh. (Unpublished) document_url: http://d-scholarship-dev.library.pitt.edu/10618/1/GAL_2011_vers2.pdf