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Retinal rod outer segment lipids form bilayers in the presence and absence of rhodopsin: a 31 P NMR study
Author(s) -
Deese Alan J.,
Dratz Edward A.,
Brown Michael F.
Publication year - 1981
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(81)80061-0
Subject(s) - citation , rhodopsin , chemistry , library science , art history , art , retinal , computer science , biochemistry
The molecular organization of the retinal rod outer segment (ROS) disc membrane has occupied the attention of many investigators recently. Studies have focussed on the protein organization [l-5], the phospholipid composition and transmembrane asymmetry [6-lo], rhodopsin-lipid interactions [l I-171, and the possible functional role of the highly polyunsaturated ROS phospholipids in visual phototransduction [ 181. One area of current interest involves studies of the influence of the various phospholipid head groups, acyl chain unsaturation, and rhodopsin on the phase polymorphism of the retinal photoreceptor membrane phospholipids. Since these ROS phospholipids are extremely polyunsaturated, with docosahexenoic acid (C22:6w3) constituting nearly 50 mol% of the total membrane fatty acids [19], great care must be taken to avoid lipid oxidative damage [20]. NMR [13--l 51, differential scanning calorimetry [2 11, and parinaric acid fluorescence studies [22] demonstrated a broad, endothermic phase transition in dispersions of bovine ROS membranes and their total extracted phospholipidswith amidpoint near4-6°C [21].The observed thermal behavior is believed due to a gel-liquid crystalline transition of a fraction of the ROS phospholipids [14,22]. Over 15-5O”C, no further distinct calorimetric transitions are detected in either preparation, although fluorescence methods suggest the onset of