A LIQUID-CRYSTALLINE MEDIUM FOR MEASURING RESIDUAL DIPOLAR COUPLINGS OVER A WIDE-RANGE OF TEMPERATURES

A mixture of dilauroyl phosphatidylcholine (DLPC) and olamidopropyl)di methylammonio-2-hydroxyl-1-propane sulfonate (CHAPSO) in water forms d isc shaped bicelles that become ordered at high magnetic fields over a wide range of temperatures. As illustrated for the FK506 binding prot ein (FKBP), large residual dipolar couplings can be measured for prote ins dissolved in low concentrations (5% w/v) of a DLPC/CHAPSO medium a t a molar ratio of 4.2:1. This system is especially useful for measuri ng residual dipolar couplings for molecules that are only stable at lo w temperatures.