High Performance Digital Console and Sample Jet

Volkman, Brian

Abstract

We request funds to replace an obsolete console on a 600 MHz NMR spectrometer, upgrade a cryoprobe to include direct detection of carbon-13, and install an autosampler to aid the drug discovery and biomolecular NMR needs of a diverse range of 10 NIH-funded investigators in the greater Milwaukee area. This instrument has been the workhorse spectrometer for the past 13 years supporting a large number of different NMR investigations including data collection for 33 high-resolution 3D structures resulting in publications that have been cited over 550 times. The console upgrade is required to install non-uniform sampling (NUS) experiments that reduce data acquisition time up to 10-fold or allow triple resonance data acquisition on previously intractable samples. The carbon-13 direct-detect cryoprobe will enable studies of large soluble and membrane protein complexes currently not possible with the existing probe. The SampleJet autosampler is required for small molecule drug discovery projects and also enables NMR spectroscopists to approach titrations and sample optimization experiments in a fundamentally new way. We describe projects from 4 major users with NIH funding and 9 minor users (6 with NIH funding) that will benefit from the requested instrumentation. The user projects span a range of structure and functional dynamics studies on soluble and integral membrane proteins and their complexes with other proteins, nucleic acids, lipids, carbohydrates and other ligands. These projects will benefit from the requested instrumentation for various reasons: drug discovery projects that will be greatly accelerated by an autosampler, samples that are poorly soluble in low salt that will benefit from a salt- tolerant cryoprobe, or large complexes including integral membrane proteins and glycoproteins that will benefit from direct carbon-13 detection. For the 7 users with structure determination projects, the NUS sampling will allow faster data collection for resonance assignments. We provide an example of the quality of NUS data from our 500 MHz spectrometer. In comparison with the current technology on this instrument, the requested upgrades will enable projects on samples that are larger, less-soluble, and less-stable. It will also enable drug discovery projects not currently practical. The instrumentation will be installed on a 600 MHz NMR spectrometer located in the Biomolecular NMR Center that already contains the necessary infrastructure for successful installation and usage (conditioned power, closed-loop chilled-water cooling system, and optimized environmental control). This instrumentation will be maintained by a staff with experience in the operation and maintenance of cryoprobes and autosamplers. Users will be trained in these technologies. Instrument time will be allocated as proposed herein. A standing local committee provides oversight of the Biomolecular NMR Center and its operations.