کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1252067 1496330 2010 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Preparation of reconstituted acetylcholine receptor membranes suitable for AFM imaging of lipid–protein interactions
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Preparation of reconstituted acetylcholine receptor membranes suitable for AFM imaging of lipid–protein interactions
چکیده انگلیسی

The nicotinic acetylcholine receptor (nAChR) has been reconstituted in POPC vesicles at high lipid–protein (L/P) ratios for the preparation of supported lipid bilayers with a low protein density for studies of protein–lipid interactions using atomic force microscopy (AFM). Initial reconstitutions using a standard dialysis method with bulk L/P ratios ranging from 20:1 to 100:1 (w/w) gave heterogeneous samples that contained both empty vesicles and proteoliposomes with a range of L/P ratios. This is problematic because empty vesicles adsorb and rupture to form bilayer patches more rapidly than do protein-rich vesicles, resulting in the loss of protein during sample washing. Although it was not possible to find reconstitution conditions that gave homogeneous populations of vesicles with high L/P ratios, an additional freeze–thaw cycle immediately after dialysis did reproducibly yield a fraction of proteoliposomes with L/P ratios above 100:1. These proteoliposomes were separated by sucrose gradient centrifugation and used to prepare supported bilayers with well-separated individual receptors and minimal adsorbed proteoliposomes. AFM images of such samples showed many small features protruding from the bilayer surface. These features range in height from 1 to 5 nm, consistent with the smaller intracellular domain of the protein exposed, and have lateral dimensions consistent with an individual receptor. Some bilayers with reconstituted protein also had a small fraction of higher features that are assigned to nAChR with the larger extracellular domain exposed and showed evidence for aggregation to give dimers or small oligomers. This work demonstrates the importance of using highly purified reconstituted membranes with uniform lipid–protein ratios for AFM studies of integral membrane protein–lipid interactions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemistry and Physics of Lipids - Volume 163, Issue 2, February 2010, Pages 117–126
نویسندگان
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