Crystalline cylindrical structures of Na(+)-bound dimyristoylphosphatidylglycerol as revealed by microcalorimetry and electron microscopy.
Multilamellar vesicles of dimyristoylphosphatidylglycerol (DMPG) in an aqueous medium of 1 M NaCl at pH 7.0 converted to defined cylindrical structures of crystalline phase, on annealing of 5 degrees C of a gel phase temperature. The new crystalline phase transformed into the liquid crystal phase at a transition point (44.2 degrees C) nearly the same as that of the protonated DMPG, but with a transition enthalpy (19.2 kcal/mol) larger than that of the Ca(2+)-bound DMPG of much higher transition temperature. Electron microscopic observations revealed that a set of outer membranes (8-10 lamellae) separated from the MLV grows into helical structures and, finally, into the crystalline cylindrical structures with an increase in annealing time.
Kodama
M
M
Department of Biochemistry, Faculty of Science, Okayama University of Science, Japan.
Miyata
T
T
Yokoyama
T
T
D002151:Calorimetry; D003461:Crystallography; D008854:Microscopy, Electron; D010715:Phosphatidylglycerols / Q000737:chemistry*; D012965:Sodium Chloride; D013696:Temperature; D013816:Thermodynamics
D010715:Phosphatidylglycerols; D012965:Sodium Chloride; C002773:dimyristoylphosphatidylglycerol