An Efficient System for 30-K MAS-NMR-DNP for Macromolecule Structure Determinations

The critical importance of solid state NMRssNMRwas recently demonstrated byafter nearly two decades of intense effortsyielding the first atomic resolution structures of the Aand Aamyloid fibrils that play acrucial role in Alzheimer s DiseaseADKey to that advance is a technique denoted as dynamic nuclearpolarizationDNPwith magic angle spinningMASFor technical reasonsdiscussed belowthese experiments have been carried out temperatures on the order ofKWhile Cryo EMscanning tunneling electron microscopySTEMand other methods provided useful informationrecent advances in MAS NMR methods have refined the structures to atomic resolution by addingNMR constraintsincluding sidechain dynamics important in protein functions and in understanding of myriad mechanisms of their actionMoreoveronly a small number of insoluble membrane proteins larger thankDa with backbone and side chain assignments completed by andgthave been deposited into the Protein Data BankHencedeveloping transformational advances for ssNMR is crucial for both structural biology and biomedical research in generalfor progress in curingAlzheimer s Disease and cancerand for providing regio specific drug binding information enabling detailing of the mechanism of action for effective drugsThis proposed Phase I SBIR will show feasibility of revolutionary advances in ultra compact super effective cryogenic heat exchangers that are small enough to fit inside MAS DNP probes thatwith the novel cryogenic system developments planned for Phase IIwill enable routine low cost MAS DNP down toKThis will dramatically reduce the amount of microwave power required for the electron spin saturation needed for the DNP methodand will thereby enable MAS DNP using advanced low cost THz solid state sources rather than expensive gyrotronsThe Phase II MAS DNP system will have zero consumption of liquid cryogensnegligible helium gas consumptiononly during sample changesaffordable equipment costsand operating costs ofonly a few dollars per hour Thousands of researchers are regularly using Nuclear Magnetic ResonanceNMRtechniqueswith a majority of the applications driven by the need for structure and function determination in biological macromoleculesThe advances developed under this project will allow every NMR laboratory that has a wide bore magnet to dramatically improve their sensitivity on solidson a budget they will be able to affordequipping biomedical researchers with superb new tools for the structure function studies of membrane proteinscellular membrane systemsand numerous other areas