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Conformational Analysis of Designed and Natural Peptides : Studies of Aromatic/Aromatic and Aromatic/Proline Interactions by NMR

Electronic Theses of Indian Institute of Science

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Title Conformational Analysis of Designed and Natural Peptides : Studies of Aromatic/Aromatic and Aromatic/Proline Interactions by NMR
 
Creator Sonti, Rajesh
 
Subject Natural Peptides
Aromatic/Aromatic Interactions
Aromatic/Proline Interactions
Peptides - Conformational Analysis
Nuclear Magnetic Resonance
Cyclic Peptide Disulfides
Cyclic Peptides
Hybrid Peptides
Beta Hairpins
Beta Sheets
Cyclic Peptide Disulfides
Designed Peptides
Proteins - Analysis
β-Hairpin
β-sheet Peptide
α/β Hybrid Peptide
Biochemistry
 
Description This thesis describes NMR studies which probe weak interactions between amino acid side chains in folded peptide structures. Aromatic/aromatic interactions between facing phenylalanine residues have been probed in antiparallel β-sheets, while aromatic/proline interactions have been examined using cyclic peptide disulfides that occur in the venom of marine cone snails. Novel intramolecular hydrogen bonded structures in hybrid peptides containing backbone homologated residues, specifically γ-amino acids, are also described.
Chapter 1 provides a brief background to the principles involved in the design of antiparallel β-sheet structures and an introduction to previous studies on aromatic/aromatic and aromatic/proline interactions in influencing peptide conformations. A summary of the NMR methods used is also presented. Chapter 2 discusses the structural characterisation of a designed 14 residue, three stranded β-sheet peptide, Boc-LFVDP-PLFVADP-PLFV-OMe (LFV14). The results described in this Chapter support the presence of multiple conformational states about the χ1 (Cα-Cβ) torsional degree of freedom for the interacting aromatic pairs in solution. Chapter 3 presents the structural characterisation of a designed 19 residue three stranded hybrid β-sheet peptide, Boc-LVβFVDPGLβFVVLDPGLVLβFVV-OMe (BBH19). β-amino acid residues (β-phenylalanine, βPhe) were incorporated at facing positions on antiparallel β-sheets. The BBH19 structure provides an example of interaction between the N and C-terminal strands in a three stranded structure with an α/β hybrid backbone. Chapter 4 focuses on studies of the conformations of the contryphan In936 (GCVDLYPWC*) from Conus inscriptus and the related peptide Lo959 (GCPDWDPWC*) from Conus loroissi. Both peptides possess a macrocyclic 23 membered ring, with multiple accessible conformational states. Chapter 5 describes conformational analysis of a novel 20 membered cyclic peptide disulfide, CIWPWC (Vi804), from Conus virgo. NMR structures were calculated for Vi804 and an analog peptide, CIDWPWC, DW3-Vi804. Chapter 6 explores the solution conformation of hybrid sequences containing α and γ residues. Oligopeptides of the type (αγ)n and (αγγ)n have been studied in solution by NMR methods. Chapter 7 provides a summary of the results described in this thesis and highlights the major conclusions.
 
Contributor Balaram, P
 
Date 2018-04-05T03:02:49Z
2018-04-05T03:02:49Z
2018-04-05
2013
 
Type Thesis
 
Identifier http://etd.iisc.ernet.in/2005/3335
http://etd.iisc.ernet.in/abstracts/4200/G25727-Abs.pdf
 
Language en_US
 
Relation G25727