title: Site-specific ϕ- and ψ-torsion angle determination in a uniformly/extensively 13C- and 15N-labeled peptide.
abstract: A solid-state rotational-echo double resonance (REDOR) NMR method was introduced to identify the ϕ- and ψ-torsion angle from a (1)H-(15)N or (1)H-(13)C' spin system of alanine-like residues in a selectively, uniformly, or extensively (15)N-/(13)C-labeled peptide. When a C(α)(i) or a (15)N peak is site-specifically obtainable in the NMR spectrum of a uniformly (15)N/(13)C-labeled sample system, the ψ- or ϕ-torsion angle specified by the conformational structure of peptide geometry involving (15)N(i)-(1)H(α)i-(15)N(i+1) or (13)C'(i-1)-(1)H(N)i-(13)C'(i) spin system can be identified based on (13)C(α)- or (15)N-detected (1)H(α)-(15)N or (1)H(N)-(13)C REDOR experiment. This method will conveniently be utilized to identify major secondary motifs, such as α-helix, β-sheet, and β-turn, from a uniformly (15)N-/(13)C-labled peptide sample system. When tested on a (13)C-/(15)N-labeled model system of a three amino acid peptide Gly-[U-(13)C, (15)N]Ala-[U-(13)C, (15)N]Leu, the ψ-angle of alanine obtained experimentally, ψ = -40 ± 30°, agreed reasonably well with the X-ray determined angle, ψ = -39°.
authors: Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. sungsool@vt.edu
authors: Sungsool
authors: S
authors: Wi
authors: Justin
authors: J
authors: Spano
mesh_terms: D000409:Alanine / Q000737:chemistry; D000465:Algorithms; D000596:Amino Acids / Q000737:chemistry; D002247:Carbon Isotopes; D020342:Finite Element Analysis; D007553:Isotope Labeling; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009587:Nitrogen Isotopes; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D011522:Protons
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D010455:Peptides; D011522:Protons; D000409:Alanine