Detection of natural abundance 1H-13C correlations of cholesterol in its membrane environment using a gradient enhanced HSQC experiment under high resolution magic angle spinning.
The quality and signal to noise ratio of a J-based HETCOR performed on a standard MAS probe have been compared with a gradient enhanced HSQC performed on a HR-MAS probe at 500 MHz. The sample selected was cholesterol, inserted at 30 mol% in acyl chain deuterated phospholipids (DMPC-d54), at a temperature where the bilayer is in a liquid crystalline phase (310 K). It is representative of any rigid molecule undergoing fast axial diffusion in a bilayer as the main movement. After optimization of the spinning rate and carbon decoupling conditions, it is shown that the ge-HSQC/MAS approach is far superior to the more conventional J-HETCOR/MAS in terms of signal to noise ratio, and that it allows the detection of all the natural abundance cross peaks of cholesterol in a membrane environment. Clear differences between the 1H and 13C chemical shifts of cholesterol in a membrane and in chloroform solution were thus revealed.
Soubias
O
O
Institut de Pharmacologie et de Biologie Structurale, CNRS and UPS, UMR 5089 205 rte de Narbonne, 31077 Toulouse, Cedex 4, France.
Piotto
M
M
Saurel
O
O
Assemat
O
O
Réat
V
V
Milon
A
A
D002247:Carbon Isotopes; D002784:Cholesterol / Q000032:analysis / Q000737:chemistry*; D004134:Dimyristoylphosphatidylcholine / Q000032:analysis / Q000737:chemistry*; D005240:Feasibility Studies; D008051:Lipid Bilayers / Q000032:analysis / Q000737:chemistry*; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000032:analysis / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011522:Protons; D013113:Spin Labels / Q000138:chemical synthesis
D002247:Carbon Isotopes; D008051:Lipid Bilayers; D008563:Membrane Lipids; D011522:Protons; D013113:Spin Labels; D002784:Cholesterol; D004134:Dimyristoylphosphatidylcholine