An HXYZ-g HR-Fast-MAS probe for Dramatically Improved Biomolecular Structure Determinations

An HXYZ g HR Fast MAS probe for Dramatically Improved Biomolecular Structure Determinations AbstractLiquid state NMR spectroscopy is arguably one of the best tools for structure determination for soluble proteinsThe method provides atomic resolution for modest molecular weight proteins and or their complexesThe method begins to have difficulty when the molecular weight of the system causes slow molecular motionwhich in turn increases the linewidth beyond the point of useful resolutionSolid state NMRssNMRmethods have progressed remarkably over the pastyears to permit improved resolution for these conditionsbut they still come well short of the goal of liquid like resolution on biological macromoleculessuch as membrane proteins and the fibrils that are central to Alzheimer s DiseaseTheHoly Grailin ssNMR would be the ability to successfully utilize the powerful suite of NMR acquisition and automated structure determination protocols developed for solution NMRwhich rely onH detected tripleand quad resonanceH decoupled schemesas such generally permitortimes higher S N than direct detectionforC andN respectivelywith solid samples ofmgThe main objective of this Phase II application is to complete the development a four channel multinuclear ssNMR probeHXYZthat has the capability of providingCNH correlations underH decoupling utilizing modestkHzto fastandgtkHzMagic Angle SpinningMASwhile detectingHThe resulting resolutionparticularly with proposed novel pulse sequenceswill be close to that of a typical liquid state experiment on proteinsFour channel multinuclear probes with gradients have been the workhorse in solution NMR for decadesbut they have not been available for ssNMRthey have been perceived to be impractically difficult to design and buildThe Phase I demonstrated feasibility of an H X Y Z narrow boreNBMAS probe based on a novelsingle coilrf circuit optimized forH detection and suitable for use at fields fromTThe Phase II probe will be compatible with automated sample exchangepulsed field gradientsPFGNB magnetsand novel NB microwave irradiation methods for Dynamic Nuclear PolarizationDNPCalculations suggestH J couplings contributeHz to the remainingH line broadening in rigid proteinsand available data suggest the probe limited resolutionfrom thermal gradients and magnetismin commercially available fast MAS probes has contributed anotherHzAchannel MAS probe with orderof magnitude lower thermal gradients that is capable ofHzH resolution on liquids is expected to enableH linewidths belowppm on most of the residues in rigid proteins atMHz and aboveThe novel circuit will also be tunable to virtually all combinations of interestsuch asHCHNHPCHHPLiCHAlSiOandHCSiRhthereby making it also invaluable in such areas as metabolismneurologymaterials sciencecatalysisand sustainable energy An HXYZ g HR Fast MAS probe for Dramatically Improved Biomolecular Structure Determinations NarrativeThousands 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 laboratoryindependent of the magnet borebe it either a narrow or wide bore in diameterto apply their liquids methods to solidson a budget they will be able to affordequipping biomedical researchers with superb new tools for the structurefunction studies of the fibrils central to Alzheimer s Diseasemembrane proteinscellular membrane systemsand numerous other areas