Journal article
Conformational manifold of alpha-aminoisobutyric acid (Aib) containing alanine-based tripeptides in aqueous solution explored by vibrational spectroscopy, electronic circular dichroism spectroscopy, and molecular dynamics simulations
Journal of the American Chemical Society, v 129(43), pp 13095-13109
31 Oct 2007
PMID: 17918837
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Replacement of the alpha-proton of an alanine residue to generate alpha-aminoisobutyric acid (Aib) in alanine-based oligopeptides favors the formation of a 3(10) helix when the length of the oligopeptide is about four to six residues. This research was aimed at experimentally identifying the structural impact of an individual Aib residue in an alanine context of short peptides in water and Aib's influence on the conformation of nearest-neighbor residues. The amide I band profile of the IR, isotropic and anisotropic Raman, and vibrational circular dichroism (VCD) spectra of Ac-Ala-Ala-Aib-OMe, Ac-Ala-Aib-Ala-OMe, and Ac-Aib-Ala-Ala-OMe were measured and analyzed in terms of different structural models by utilizing an algorithm that exploits the excitonic coupling between amide I' modes. The conformational search was guided by the respective 1H NMR and electronic circular dichroism spectra of the respective peptides, which were also recorded. From these analyses, all peptides adopted multiple conformations. Aib predominantly sampled the right-handed and left-handed 3(10)-helix region and to a minor extent the bridge region between the polyproline (PPII) and the helical regions of the Ramachandran plot. Generally, alanine showed the anticipated PPII propensity, but its conformational equilibrium was shifted towards helical conformations in Ac-Aib-Ala-Ala-OMe, indicating that Aib can induce helical conformations of neighboring residues positioned towards the C-terminal direction of the peptide. An energy landscape exploration by molecular dynamics simulations corroborated the results of the spectroscopic studies. They also revealed the dynamics and pathways of potential conformational transitions of the corresponding Aib residues.
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Details
- Title
- Conformational manifold of alpha-aminoisobutyric acid (Aib) containing alanine-based tripeptides in aqueous solution explored by vibrational spectroscopy, electronic circular dichroism spectroscopy, and molecular dynamics simulations
- Creators
- Reinhard Schweitzer-Stenner - Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, USA. RSchweitzer-Stenner@drexel.eduWidalys GonzalesGregory T BourneJianwen A FengGarland R Marshall
- Publication Details
- Journal of the American Chemical Society, v 129(43), pp 13095-13109
- Publisher
- American Chemical Society; Washington, DC
- Grant note
- GM 08460 / NIGMS NIH HHS GM 008802 / NIGMS NIH HHS
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemistry
- Web of Science ID
- WOS:000250818900044
- Scopus ID
- 2-s2.0-35848970565
- Other Identifier
- 991014878599804721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Chemistry, Multidisciplinary