Abstract
The Langmuir monolayer of aequorin and apoaequorin was studied by infrared reflection-absorption spectroscopy (IRRAS) and polarization-modulated IRRAS techniques. The α-helices in the aequorin Langmuir monolayer were parallel to the air - water interface at zero surface pressure. When the surface pressure increased to 15 mN·m_1, the α-helices became tilted and the turns became parallel to the air-water interface. As for apoaequorin, the α-helices were also parallel to the air-water interface at 0 mN·m-1. However, the α-helix became tilted and the turns became parallel to the air-water interface quickly at 5 mN·m -1. With further compression of the apoaequorin Langmuir monolayer, the orientation remained the same. The different behaviors of aequorin and apoaequorin at the air-water interface were explained by the fact that aequorin formed dimers at the air - water interface but apoaequorin was a monomer. It is more difficult for a dimer to be tilted by the compression of the Langmuir monolayer.
Original language | English (US) |
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Pages (from-to) | 4146-4151 |
Number of pages | 6 |
Journal | Journal of Physical Chemistry B |
Volume | 112 |
Issue number | 13 |
DOIs | |
State | Published - Apr 3 2008 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry