Beating Boltzmann: Using hyperpolarized xenon to analyze biomolecules

ANYL 37

David Wemmer, dewemmer@lbl.gov1, Tom J. Lowery2, Sandra Garcia3, Lana J. Chavez3, and Alexander Pines, pines@cchem.berkeley.edu4. (1) Department of Chemistry, Univ of California Berkeley, Berkeley, CA 94720, (2) Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, (3) Department of Chemistry, University of California and Berkeley Lab, MC-1460, Berkeley, CA 94720, (4) Chemistry, U of CA and LBNL, University Avenue, Berkeley, CA 94720
We present methods to exploit strong signals of hyperpolarized xenon in biological systems. We showed that xenon interacts directly with proteins, and protein-induced shifts of xenon signals report on binding interactions. Since xenon exchanges rapidly among available binding sites the detection sensitivity is limited by ability to measure small shifts. To improve the detection threshold, we introduced xenon biosensors. These contain a molecular cage that binds xenon and gives slow exchange NMR signals. We covalently attach ligands to the cage to introduce specific intermolecular interactions, and have shown that the xenon shift responds to ligand binding events. The ligands can also be used to cause spatial localization of cages and xenon, useable in an MRI mode to determine the spatial distribution of the ligand's interaction partner. Favorable exchange properties of xenon in cages with that in water enabled us to enhance detection sensitivity relative to normal FT NMR.
 

NMR Then and Now: Honoring Ted Becker, Recipient of the Analytical Chemistry Service Award Supported by Varian, Inc
2:15 PM-4:45 PM, Sunday, 10 September 2006 Moscone Center -- Room 123, Oral

Division of Analytical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006