NMR structural studies of proteins in membranes and other supramolecular assemblies
University of Kentucky
1976 - 2000
University of Pennsylvania
The overall goal of the research program is to develop protein expression systems, instrumentation, and experimental methods so that NMR spectroscopy can be used to study all of the proteins encoded in a genome. Substantial progress has been made through the development of high-resolution solid-state NMR methods, and it is now possible obtain completely resolved and assigned spectra of proteins in membrane bilayers and virus particles.
Membrane proteins are of particular interest, since they constitute about 30% of a genome, representing a major area of research in structural biology, and present challenging systems for NMR spectroscopy. The HIV-1 accessory protein Vpu is one of the principal systems currently being investigated. Vpu has two biological functions that affect the virulence of AIDS. In its phosphorylated form, Vpu enhances both the processing of the envelope glycoprotein gp160, and the degradation of CD4 molecules in infected cells. The protein also acts as an ion channel, an activity associated with its trans-membrane helix and related to its ability to enhance the budding of new virus particles. Several other membrane proteins are under investigation, including the membrane proteins MerF and MerT responsible for transporting mercury across membranes into the cytoplasm where it is reduced to non-toxic and volatile metallic mercury.
The principal system under investigation is G-protein coupled receptors. With seven trans-membrane helices and about 350-residues they represent a significant technical challenge and motivated us to develop a new method of structure determination, rotationally aligned solid-state NMR. This enables the structures of GPCRs and other membrane proteins to be determined under near-native conditions in liquid crystalline phospholipid bilayers. We have determined the structure of the chemokine receptor CXCR1 using this approach.
Primary Research Area
We utilize the Biotechnology Resource Center as a magnet for training students with diverse
backgrounds, and accelerating their acceptance into mainstream scientific research. An example of visitors in various categories are listed above. These include local high school students, undergraduate students supported by the STARS program, graduate students and postdoctoral scholars.
- Cook GA, Dawson LA, TIan Y, Opella SJ "Three-dimensional structure and interaction studies of Hepatitis C Virus p7 in 1,2-dihexanoyl-sn-glycero-2-phosphocholine by solution nuclear magnetic resonance", Biochemistry, 2013, Vol. 52, 5295-5303
- Lu GJ, Opella SJ "Motion-adapted pulse sequences for oriented sample (OS) solid-state NMR of biopolymers", Journal of Chemical Physics, 2013, Vol. 139, 084203
- Lu GJ, Tian Y, Vora N, Marassi FM, Opella SJ "The structure of the mercury transporter MerF in phospholipid bilayers: A large conformational rearrangement results from N-terminal truncation", Journal of the American Chemical Society, 2013, Vol. 135, 9299-9302
- Opella SJ "Structure determination of membrane proteins by nuclear magnetic resonance spectroscopy", Annual Reviews of Analytical Chemistry, 2013, Vol. 6, 305-328
- Opella SJ "Structure determination of membrane proteins in their native phospholipid bilayer environment by rotationally aligned solid-state NMR spectroscopy", Accounts of Chemical Research, 2013, Vol. 46, 2145-2153
- Park SH, Das BB, Casagrande F, Tian Y, Nothnagel HJ, Chu M, Kiefer H, Maier K, De Angelis AA, Marassi FM, Opella SJ "Structure of the chemokine receptor CXCR1 in phospholipid bilayers", Nature, 2012, Vol. 7426, 779-783