Abstract
The protein conformation and orientation of Photosystem I (PS I) particles have been investigated by a combination of ultraviolet circular dichroism and polarized infrared spectroscopies. These PS I particles have been studied before and after reconstitution in phosphatidylcholine vesicles. The native state of the pigments of PS I was characterized by monitoring the low-temperature fluorescence emission spectra as well as the visible CD and linear dichroism spectra at room temperature. Computed analysis of the ultraviolet CD spectra of PS I complex indicates that the secondary structure of the protein is largely α-helical (52 ± 4%) with a very low amount of β-structure. Polarized infrared difference spectra of oriented PS I show a significant orientation of these α-helical segments with the α-helix axes tilted on the average at approx. 35° from the membrane normal.
Original language | English (US) |
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Pages (from-to) | 640-647 |
Number of pages | 8 |
Journal | BBA - Bioenergetics |
Volume | 767 |
Issue number | 3 |
DOIs | |
State | Published - Dec 18 1984 |
Keywords
- (Pea chloroplast)
- CD
- Membrane reconstitution
- Photosystem I
- Polarized infrared spectroscopy
- α-Helix orientation
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology