Table of Services

Spectroscopy Support Facility

Function

The primary functions of the Spectroscopy Support Facility (SSF) are to maintain and operate instrumentation for high-field NMR and optical (fluorescence and circular dichroism) spectroscopy, to implement and develop methods for biomolecular studies, and to provide technical expertise and assistance to users. A 300 MHz spectrometer is available for NMR analysis of small organic compounds and heteronuclear experiments on isotopically labeled enzymes. A 600 MHz instrument is used for applications such as analysis of complex synthetic compounds, NMR structure determination of peptides, proteins or nucleic acids, studies of protein folding and dynamics using NMR relaxation methods or hydrogen-deuterium exchange, macromolecular interactions, etc. Investigators can submit samples to facility personnel for routine NMR analysis on either spectrometer, or they can be trained to operate the instruments under supervision of facility personnel. The more demanding applications typically are collaborative projects.

The 300 MHz instrument is also used for magnetic resonance micro-imaging of small animals (primarily mice). Small-animal imaging services are offered through the Biological Imaging Facility. For further information contact Dr. Harvey Hensley.

The facility also provides instrumentation and support for circular dichroism (CD) spectroscopy, which is used for conformational analysis of optically active molecules, including peptides and proteins, and studies of protein stability and folding. The facility recently acquired a new scanning fluorescence spectrometer, which is available for a wide range of applications, including ligand binding measurements and studies of macromolecular structure, interaction and assembly.

Description

The 300 MHz NMR spectroscopy instrument consists of a wide-bore superconducting magnet and a Bruker DRX300 WB console. Image analysis can be performed on the Silicon Graphics workstation provided with the Bruker console, or off line on a PC workstation using commercial software or routines written in the IDL programming language. An internal web site has been developed to allow users to access and work with the images. The 600 MHz NMR spectrometer was upgraded in 1995 with a Bruker DMX 600 console fully equipped for high-resolution biological applications, such as heteronuclear, multidimensional and gradient-enhanced experiments. Among a range of homo- and heteronuclear probes, the one used most often (for studies of 13C- and/or 15N-labeled samples) is a 5 mm triple-resonance probe with actively shielded x, y, z gradient coils. The facility maintains several graphics workstations for data acquisition and processing, assignment work, and structure calculations. The CD spectrometer (Aviv 62ABS) operates over the range 190-650 nm and is equipped with a thermoelectric cuvette holder. The newly acquired scanning spectrofluorometer (PTI Quantum Master 2000) features a high-intensity Xe arc light source, a second emission channel and motorized polarizers for fluorescence depolarization measurements, and a computer-controlled titrator.