Depth-dependent analysis of membranes using benzophenone-based phospholipids.
Any attempt to probe the membrane hydrophobic core with chemical reagents necessitates the use of reactive intermediates like carbenes and nitrenes, which can insert into C-H bonds. Several photoactivable reagents based on carbenes and nitrenes have been reported. However, the high reactivity of these reagents, often leads to very low insertion yields. We report here a high degree of cross-linking (35-40%) achieved with three benzophenone-based phospholipids and analyze the carbon functionalization data using a multiple Gaussian function. These phospholipids are so designed so as to permit depth-dependent labeling in membranes. Single bilayer vesicles were prepared from these phospholipids and dimyristoylphosphatidylcholine. The cross-linked product was isolated and characterized by mass spectroscopy. The results obtained indicated that the cross-linked product was dominated by dimeric product formed by intermolecular cross-linking. The Gaussian analysis used here provides insight into the relative depths of the probes inside the membrane.
John
B
B
Department of Chemistry and Biotechnology Center, Indian Institute of Technology Bombay, Powai.
Kumar
E R
ER
Lala
A K
AK
D001577:Benzophenones / Q000737:chemistry / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry / Q000378:metabolism; D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism*; D013058:Mass Spectrometry; D015394:Molecular Structure; D016011:Normal Distribution; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism*; D019920:Photoaffinity Labels / Q000737:chemistry / Q000378:metabolism
D001577:Benzophenones; D003432:Cross-Linking Reagents; D008051:Lipid Bilayers; D010743:Phospholipids; D019920:Photoaffinity Labels; D004134:Dimyristoylphosphatidylcholine