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FTIR-Spectroscopy of multistranded coiled coil proteins
T Heimburg1, J Schünemann, K Weber
1Max Planck Institute for Biophysical Chemistry Departments of Spectroscopy and Biochemistry D-37018 Goettingen, Federal Republic of Germany. theimbu@gwdg.de
Biochemistry
|October 3, 1999
Summary
Infrared spectroscopy reveals distinct vibrational spectra for coiled coils. Higher-order coiled coils show spectral patterns correlating with helical distortion and supercoil pitch.
Area of Science:
- Biophysics
- Spectroscopy
- Protein Structure
Background:
- Coiled coils are protein structures formed by alpha-helices.
- Dimeric coiled coils exhibit unique vibrational spectra in the amide I region due to helical distortion.
- Classical alpha-helices display a single band in this region.
Purpose of the Study:
- Investigate coiled coils of different orders (trimers, tetramers, pentamers) using infrared (IR) spectroscopy.
- Correlate spectral band patterns with superhelical pitch and helical distortion in various coiled coil structures.
Main Methods:
- Infrared (IR) spectroscopy was employed to analyze coiled coil structures.
- Vibrational spectra in the amide I region were examined.
- Spectral band positions and separation were analyzed in relation to superhelical pitch.
Main Results:
- All investigated coiled coils (dimeric, trimeric, tetrameric, pentameric) showed a characteristic three-band pattern in their amide I spectra.
- The separation and position of these bands correlated with the superhelical pitch and degree of helical distortion.
- Tropomyosin dimer showed the most pronounced spectral anomaly, while COMP and leucine zipper mutants exhibited the least distortion.
Conclusions:
- The three-band spectral pattern is characteristic of coiled coils, with variations reflecting helical distortion.
- Superhelical pitch is a key determinant of spectral anomaly in coiled coils.
- IR spectroscopy provides a sensitive method for probing coiled coil structure and distortion.