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Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
Single peptide bonds exhibit poly(pro)II ("random coil") circular dichroism spectra
Isa Gokce1, Robert W Woody, Gregor Anderluh
1Institute of Cell and Molecular Biosciences, University of Newcastle-upon-Tyne, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK.
Journal of the American Chemical Society
|July 7, 2005
Summary
Simple peptide bonds exhibit a preferred conformation, influencing the spectra of disordered proteins. This finding stems from analyzing far-UV circular dichroism spectra of amino acid derivatives.
Area of Science:
- Biophysical Chemistry
- Spectroscopy
- Protein Structure
Background:
- The far-UV circular dichroism (CD) spectra of polypeptides are crucial for understanding protein secondary structure.
- The polyproline (PP) II conformation is a common disordered state observed in proteins.
Purpose of the Study:
- To investigate the conformational preferences of simple peptide bonds using far-UV CD spectroscopy.
- To determine the structural basis for the characteristic PP II spectrum.
Main Methods:
- Measurement of far-UV circular dichroism spectra for various amino acid derivatives with single peptide bonds.
- Analysis of spectral changes upon heating to identify conformational transitions.
Main Results:
- N-acetyl-alanine and Gly-Ala derivatives exhibited a polyproline (PP) II-like spectrum.
- Alaninamide showed a weak positive signal, and Ala-Gly did not display a PP II spectrum.
- A two-state transition was observed upon heating, consistent with PP II polypeptides.
Conclusions:
- The characteristic PP II negative maximum at <200 nm arises from the coupling of the peptide bond to the N-terminal chiral alpha-carbon.
- The simplest peptide bonds possess a preferred conformation that dictates the CD spectra of disordered proteins, regardless of size.
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