Raman spectral evidence for hydration forces between collagen triple helices.
Hydration forces are thought to result from the energetic cost of water rearrangement near macromolecular surfaces. Raman spectra, collected on the same collagen samples on which these forces were measured, reveal a continuous change in water hydrogen-bonding structure as a function of separation between collagen triple helices. The varying spectral parameters track the force-distance curve. The energetic cost of water "restructuring," estimated from the spectra, is consistent with the measured energy of intermolecular interaction. These correlations support the idea that the change in water structure underlies the exponentially varying forces seen in this system at least over the 13-18-A range of interaxial separations.
Leikin
S
S
Division of Computer Research and Technology and National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Parsegian
V A
VA
Yang
W
W
Walrafen
G E
GE
D003094:Collagen / Q000737:chemistry*; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D009994:Osmolar Concentration; D011487:Protein Conformation; D013059:Spectrum Analysis, Raman / Q000379:methods; D013314:Stress, Mechanical; D014867:Water
D046911:Macromolecular Substances; D014867:Water; D003094:Collagen