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Disposition of water in chloroplast coupling factor 1 (CF 1 )
Author(s) -
Ibel Konrad,
Engelbrecht Siegfried,
Wagner Richard,
Andreo Carlos S.,
Junge Wolfgang
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80800-2
Subject(s) - glycerol , volume (thermodynamics) , chemistry , aqueous solution , analytical chemistry (journal) , neutron scattering , crystallography , scattering , chromatography , thermodynamics , organic chemistry , physics , optics
Small‐angle neutron scattering experiments were performed in dilute aqueous solutions of chloroplast F 1 ‐ATPase. By contrast variation in 1 H 2 O/ 2 H 2 O mixtures and when using different concentrations of glycerol in 2 H 2 O, structural information on the spatial distribution of dry protein and water was obtained. The maximum distance within latent and active CF 1 was 12 nm. the shape of CF 1 was globular. The total volume of CF 1 was 900 nm 3 , and its dry volume (excluding the volume of one water molecule per two exchangeable hydrogen atoms) was 400 nm 3 . A volume of 670 nm 3 was inaccessible to glycerol at low glycerol concentrations (less than 25%). At higher concentrations (up to 50%) a volume of 460 nm 3 was excluded to glycerol. Within the resolution of our experiment (1.6 nm) there was no evidence for particular water‐rich regions or of secluded water spaces or any particular places for glycerol exchange. Upon thiol activation of the latent enzyme only small changes in structure were detectable just at the limits of the experimental error. They suggest an enhancement of the surface roughness.