Gary A. Lorigan
Biophysical chemistry, membrane proteins, phospholipids, and magnetic resonance spectroscopy
The research in my laboratory is focused upon the utilization of magnetic resonance spectroscopy to investigate the structural and dynamic properties of membrane-bound proteins and peptides and their interactions within the lipid bilayer. We are specifically interested in developing and applying state-of-the-art nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopic techniques to study proteins inserted into oriented phospholipid bilayers.
Membrane proteins (which make up approximately one-third of the total number of proteins) are responsible for many important properties and functions of biological systems: they transport ions and molecules across the membrane, they act as receptors, and they have roles in the assembly, fusion, and structure of cells and viruses. Despite the abundance and clear importance of these membrane proteins and peptides, only a minute amount of information regarding these systems exists.
High-resolution multi-nuclear solid-state NMR spectroscopy is a powerful technique that can yield pertinent structural, orientational, and dynamic information about membrane protein systems when they are aligned with the direction of the static magnetic field. EPR spectroscopy coupled with site-specific nitroxide spin labeling can determine motional parameters and measure the distances between protein residues. Also, by placing specific nitroxide and 2H spin labels along the hydrophobic lipid acyl chain, membrane protein insertion depth can be monitored by observing the presence of any spectral line broadening or intrinsic relaxation changes (EPR and NMR).
Inbaraj, J. J., Laryukhin, M., and Lorigan, G. A. “Determining the Helical Tilt Angle of a Transmembrane Helix in Mechanically Aligned Lipid Bilayers using EPR Spectroscopy” J. Am. Chem. Soc. (2007) 129, 2725-2734.
Abu-Baker, S., Lu, J. X., Chu, S., Shetty, K. K., Gor’kov, P. L., and Lorigan, G. A. “The Structural Topology of Wild-type Phospholamban in Oriented Lipid Bilayers using 15N Solid-state NMR Spectroscopy” Protein Sci. (2007) 16, 2345-2349.
Abu-Baker, S., Lu, J. X., Chu, S., Brinn, C. C., Makaroff, C. A., and Lorigan, G. A. “Side Chain and Backbone Dynamics of Phospholamban in Phospholipid Bilayers Utilizing 2H and 15N Solid-State NMR Spectroscopy” Biochemistry (2007) 46, 11695-11706.
Mayo, D. J., Inbaraj, J. J., Subbaraman, N., Grosser, S. M., Chan, C. A., and Lorigan, G. A. “Comparing the Structural Topology of Integral and Peripheral Membrane Proteins Utilizing EPR Spectroscopy” J. Am. Chem. Soc. (2008) 130, 9656-9657.
Newstadt, J. P., Mayo, D. J., Inbaraj, J. J., Subbaraman, and Lorigan G. A. “Determining the helical tilt of membrane peptides using electron paramagnetic resonance spectroscopy” J. Magn. Reson. (2009) 198, 1-7.
Gull, S. V., Sharma, G., Borbat, P., Freed, J. H., Ghimire, H., Benedikt, M. R., Holt, N. L., Lorigan, G. A., Rege, K., Mavroidis, C., and Budil, D. E. “Molecular-Scale Force Measurement in a Coiled-Coil Peptide Dimer by Electron Spin Resonance” J. Am. Chem. Soc. (2009) 131, 5374-5375.
Ghimire, H. McCarrick, R. M., Budil, D. E., Lorigan, G. A.. "Significantly Improved Sensitivity of Q-Band PELDOR/DEER Experiments Relative to X-Band Is Observed in Measuring the Intercoil Distance of a Leucine Zipper Motif Peptide (GCN4-LZ)" Biochemistry, (2009), 48 (25) 5782-5784.
J. X. Lu, K. Damodaran, and G. A. Lorigan, “Probing Membrane Topology by 1H-13C Heteronuclear Dipolar Solid-State NMR Spectroscopy”, J. Magn. Reson., 176, 283-287 (2006).
W. J. Gibbons, E. S. Karp, N. A. Cellar, R. E. Minto, and G. A. Lorigan, “Solid-State NMR Studies of a Diverged Microsomal Amino-Proximate Δ12 Desaturase Peptide Reveal Causes of Stability in Bilayer: Tyrosine Anchoring and Arginine Snorkeling”, Biophys. J., 90, 1249-1259 (2006).
J. X. Lu, J. Blazyk, and G. A. Lorigan, “Exploring Membrane Selectivity of the Antimicrobial Peptide KIGAKI Using Solid-State NMR Spectroscopy”, BBA-Biomembrane, 1758, 1303-1313 (2006).
R. E. Lee, K. Damodaran, S. X. Yi, and G. A. Lorigan, “Rapid Cold-Hardening Increases Membrane Fluidity and Cold Tolerance of Insect Cells”, Cryobio., 52, 459-463 (2006).
E. S. Karp, E. S. Tiburu, S. Abu-Baker, and G. A. Lorigan, “The Structural Properties of the Transmembrane Segment of the Integral Membrane Protein Phospholamban Utilizing 13C CPMAS, 2H, and REDOR Solid-State NMR Spectroscopy”, BBA-Biomembrane, 1758, 772-780 (2006).
E. K. Tiburu, E. S. Karp, G. Birrane, J. O. Struppe, S. Chu, G. A. Lorigan, S. Avraham, and H. K. Avraham, “31P and 2H Relaxation Studies of Helix VII and the Cytoplasmic Helix of the Human Cannabinoid Receptors Utilizing Solid State NMR Techniques”, Biochemistry, 45, 7356-7365 (2006).
J. J. Inbaraj, T. B. Cardon, M. Laryukhin, S. Grosser, and G. A. Lorigan, “Determining the Topology of Integral Membrane Peptides Using EPR Spectroscopy”, J. Am. Chem. Soc., 128, 9549-9554 (2006).
E. S. Karp, J. J. Inbaraj, M. Laryukhin, and G. A. Lorigan, “Electron Paramagnetic Resonance Studies of an Integral Membrane Peptide Inserted into Aligned Phospholipid Bilayer Nanotube Arrays”, J. Am. Chem. Soc., 128, 12070-12071 (2006).
S. Abu-Baker and G. A. Lorigan, “Phospholamban and its Phosphorylated Form Interact Differently with Lipid Bilayers: A 31P, 2H, and 13C Solid-State NMR Spectroscopic Study”, Biochemistry, 45, 13312-13322 (2006).