Abstract
Microwave dielectric spectroscopy can measure the rotational mobility of water molecules that hydrate proteins and the hydration-shell volume. Using this technique, we have recently shown that apart from typical hydrating water molecules with lowered mobility there are other water molecules around the actin filaments (F-actin) which have a much higher mobility than that of bulk water [Biophys. J. 85 (2003) 3154]. We report here that the volume of this water component (hyper-mobile water) markedly increases without significant change of the volume of the ordinary hydration shell when the myosin motor-domain (S1, myosin subfragment-1) binds to F-actin. No hyper-mobile component was found in the hydration shell of S1 itself. The present results strongly suggest that the solvent space around S1 bound to F-actin is diffusionally asymmetric, which supports our model of force generation by actomyosin proposed previously [op. cit.].
Original language | English |
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Pages (from-to) | 340-346 |
Number of pages | 7 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 322 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2004 Sep 10 |
Keywords
- Actin filament
- Actomyosin
- Brownian ratchet
- Hyper-mobile water
- Linear motor mechanism
- Microwave dielectric spectroscopy
- Negative hydration
- Protein hydration
- Urea hydration
- Water structure breaker
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology