Ice formation in model biological membranes is studied by SAXS and WAXS in
the presence of cryoprotectors: dimethyl sulfoxide and glycerol. Three types of
phospholipid membranes: DPPC, DMPC, DSPC are chosen for the investigation as
well-studied model biological membranes. A special cryostat is used for sample
cooling from 14.1C to -55.4C. The ice formation is only detected by WAXS in
binary phospholipid/water and ternary phospholipid/cryoprotector/water systems
in the condition of excess solvent. Ice formation in a binary
phospholipid/water system creates an abrupt decrease of the membrane repeat
distance by delta-d, so-called ice-induced dehydration of intermembrane space.
The value of delta-d decreases as the cryoprotector concentration increases.
The formation of ice does not influence the membrane structure (delta-d = 0)
for cryoprotector mole fractions higher than 0.05.Comment: PDF: 9 pages, 3 figures; sourse in MS Wor