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High‐pressure 1 H NMR on model biomembranes: a study of the local anaesthetic tetracaine incorporated into POPC lipid bilayers
Author(s) -
Eisenblätter Jörg,
Zenerino Axel,
Winter Roland
Publication year - 2000
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/1097-458x(200008)38:8<662::aid-mrc707>3.0.co;2-h
Subject(s) - popc , chemistry , tetracaine , vesicle , lipid bilayer , membrane , biochemistry , medicine , anesthesia , lidocaine
One‐ and two‐dimensional 1 H NMR experiments were performed at ambient and elevated pressures to study structural and conformational properties of the local anaesthetic tetracaine (TTC) incorporated into 1‐palmitoyl‐2‐oleoyl‐ sn ‐glycero‐3‐phosphatidylcholine (POPC) lipid bilayers, and also the lipid– tetracaine interaction. For this purpose, a 400 MHz high‐pressure, high‐resolution NMR probe was developed, operating in the pressure range 1– 3000 bar at temperatures up to 80 ° C. We obtained a linewidth better than 2.5 Hz for a 5 mm sample of 10% CHCl 3 in CDCl 3 in the high‐pressure environment. The results from two‐dimensional 1 H, 1 H NOESY experiments show that the charged form of TTC is not expelled from unilamellar POPC vesicles at pressures up to about 2 kbar. Intramolecular cross peaks indicate that TTC is incorporated in a bent conformation, located in the headgroup region at ambient pressure, but embedded deeper in the membrane interior at higher pressures. Copyright © 2000 John Wiley & Sons, Ltd.