We have developed
a device that can be installed in our shared commercial 500
MHz NMR instrument, to move a sample from its usual position
at the center of the magnet out to a lower-field position
above the magnet, and back, with a minimum round-trip time
of 100 msec. This permits us to insert a low-field interval
into any pulse sequence, that can be used to study relaxation
or cross-polarization rates at the lower field. At these lower
fields, heteronuclear dipolar relaxation between spins, which
produces NOE's (nuclear Overhauser Effects), is enhanced compared
to other competing relaxation mechanisms. Major uses of this
device are: checking and extending NMR-based studies of protein
dynamics, including ligand dynamics; and studies of nucleic
acid backbone geometry based on proton-to-31P NOE. Currently
we are testing the apparatus with short DNA duplexes. We also
expect to participate in collaborations with others at Brandeis,
using this device.
| Dr. Redfield is a Member of the National
Academy of Sciences and a Fellow of the American Academy
of Arts and Sciences. |
Selected
Publications:
"Conformational
and Dynamic Differences Between N-ras P21 Bound to GTPgS
and to GMPPNP as Studied by NMR" (J. S. Hu & A. G. Redfield)
Biochemistry 36, 5045-5052 (1997).[abstract]
"Development
of a Field Cycling NMR System for PQR Detection in Biopolymers"
(D. Ivanov & A. G. Redfield) Zeitschrift fur Naturforschung
53a, 269-272 (1998). [abstract]
"Development
of a Field-Cycling NMR Method to Study Quadrupolar Nuclei
in Biological Systems." Ph.D. Thesis, Dmitri Ivanov,
January, 2001.
"Boron-11 pure quadrupole resonance investigation
of peptide boronic acid inhibitors bound to alpha-lytic
protease", Ivanov D, Bachovchin WW, Redfield AG, Biochemistry,
41:1587-90. (2002) [abstract]
"Field-cycling method with central transition readout
for pure quadrupole resonance detection in dilute systems",
Ivanov D, Redfield AG., J Magn Reson., 166:19-27
(2004). [abstract]
"High-resolution field-cycling NMR studies of a DNA
octamer as a probe of phosphodiester dynamics and comparison
with computer simulation", Roberts MF, Cui Q, Turner
CJ, Case DA, Redfield AG. Biochemistry, 43:3637-50
(2004). [abstract]
Last
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