Development of the nanodisc technology:
(1) Characterization of self-assembly of polymer & lipids, peptide & lipids, or protein & lipids to form discoidal nanoparticles (called nanodiscs).
(2) Evaluation of the lipid bilayer properties of different types of nanodiscs.
(3) Characterization of fusion, lipid exchange, and lipid/protein dynamics by solid-state NMR, dynamic light scattering, and high-speed-AFM.
(4) Measurement of RDCs (residual dipolar couplings) and RQCs (residual quadrupolar couplings) from small molecules/drugs/RNA/metabolite by NMR using the nanodiscs alignment medium.
Detergent-free isolation and functional reconstitution of membrane proteins:
(1) Isolation of cytochrome proteins for NMR and functional studies.
(2) Isolation of GPCRs, APP, and other membrane proteins.
Protein aggregation implicated in Alzheimer's disease, type-2 diabetes, and other amyloid diseases:
(1) Investigation of the roles of zinc, insulin, and pH on the amyloid aggregation of human-amylin (or IAPP).
(2) Structural studies on toxic amyloid intermediates.
(3) Investigating the roles of lipids and lipid membrane on the amyloid aggregation of IAPP, synuclein, and/or amyloid-beta.
(4) Investigation of the polymorphic structural aggregates of amyloid proteins.
Electron transfer kinetics by stop-flow experiments on cytochrome P450s.
Drug metabolism by P450 enzymes
Membrane proteins act as enzymes, regulate transport processes, and play a central role in intercellular communication. In order to understand the diverse functions of membrane proteins and to engineer these functions for biomedical or biotechnological purposes, it is necessary to determine their high-resolution structure and describe their dynamics. The structure determination of membrane proteins is one of the most important and challenging aspects of science at the present time. Solid-state NMR spectroscopy is an ideal technique for immobile and non-crystalline proteins that are difficult to study by X-ray crystallography or by solution NMR.
The development of solid-state NMR methods and their applications to determine the structure and describe the dynamics of membrane proteins are the main goals of the research program. The biology of the research program involves the preparation of peptides and proteins associated with membranes through synthetic or molecular biological methods. All aspects of sample preparation are optimized including the incorporation of specific and selective isotopic labels, isolation, purification, and final preparation of NMR samples. Antimicrobial peptides, toxins, cytochrome b5, myelin basic protein, and amyloid peptides are some of the systems currently under investigation by this group. Solid-state NMR experiments on membrane proteins incorporated in oriented and unoriented phospholipid bilayers and solution NMR experiments on membrane proteins in detergent micelles or lipid bicelles are performed to determine the structure of membrane proteins.
Solid-state NMR spectroscopy is one of the premier methods for studying the structure and dynamics of molecules in solids. Ramamoorthy's research program orchestrates the theoretical design, experimental demonstration, and application of new and cutting-edge solid-state NMR spectroscopic methods to study the structure and properties of molecules in single crystalline, liquid crystalline, polycrystalline, and amorphous phases. The design of solid-state NMR methods is composed of a variety of sophisticated techniques including specifically constructed multiple radio-frequency pulses, magic-angle spinning, multiple resonance schemes, sensitivity enhancement procedures, and selective observation or hybridization of them. This basic research on spin physics encompasses theoretical and experimental aspects of spin engineering, computer simulations, and instrumentation.