Low-ε Static Probe Development for15N-1H Solid-state NMR Study of Membrane Proteins for an 800 MHz NB Magnet

Abstract

H heteronuclear dipolar coupling in dilute membrane proteins oriented in hydrated anddielectrically lossy lipid environments. The system employed a 800 MHz narrow-bore magnet. A solenoid coilstrip shield was used to reduce deleterious RF sample heating by minimizing the conservative electric fieldsgenerated by the double-tuned resonator at high magnetic fields. The probe's design, construction, andperformance in solid-state NMR experiments at high magnetic fields are described here. Such high-resolutionsolid-state NMR spectroscopic analysis of static oriented samples in hydrated phospholipid bilayers or bicellescould aid the structural analysis of dilute biological membrane proteins.Key Words : Solid-state NMR probe, Low- e, Probe design, Membrane proteins, BicellesIntroductionMembrane proteins are important in various essentialsystems and regulatory processes, ranging from the com-plicated network of cellular communications to the meta-bolism and breaking down of unwanted substances in thehuman body. Hundreds of diseases involve the mis-foldingor mis-assembling of integral membrane proteins and over60% of all drug molecules target membrane proteins.Despite their importance, these protein's intrinsic structure-function relationships are not understood as their three-dimensional structures have not been fully elucidated. Thestudy of membrane proteins by current methods is hamperedby the need of a native bilayer environment, which is diffi-cult using most biophysical techniques. They are notoriouslydifficult to crystallize for X-ray crystallography and theirslow reorientation rates when combined with lipids or deter-gents hinder the use of conventional solution NMR (NuclearMagnetic Resonance) techniques. Solid-state NMR spectroscopy is a relatively new meansof investigating the structures of solid biological samples.