title: On the potential of hyperpolarized water in biomolecular NMR studies.
abstract: A main obstacle arising when using ex situ hyperpolarization to increase the sensitivity of biomolecular NMR is the fast relaxation that macromolecular spins undergo upon being transferred from the polarizer to the spectrometer, where their observation takes place. To cope with this limitation, the present study explores the use of hyperpolarized water as a means to enhance the sensitivity of nuclei in biomolecules. Methods to achieve proton polarizations in excess of 5% in water transferred into the NMR spectrometer were devised, as were methods enabling this polarization to last for up to 30 s. Upon dissolving amino acids and polypeptides sited at the spectrometer into such hyperpolarized water, a substantial enhancement of certain biomolecular amide and amine proton resonances was observed. This exchange-driven (1)H enhancement was further passed on to side-chain and to backbone nitrogens, owing to spontaneous one-bond Overhauser processes. (15)N signal enhancements >500 over 11.7 T thermal counterparts could thus be imparted in a kinetic process that enabled multiscan signal averaging. Besides potential bioanalytical uses, this approach opens interesting possibilities in the monitoring of dynamic biomolecular processes, including solvent accessibility and exchange process.
authors.affiliation: Chemical Physics Department, Weizmann Institute of Science , 205 Herzl Street, Rehovot 76100, Israel.
authors.forename: Talia
authors.initials: T
authors.lastname: Harris
authors.forename: Or
authors.initials: O
authors.lastname: Szekely
authors.forename: Lucio
authors.initials: L
authors.lastname: Frydman
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D007700:Kinetics; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011522:Protons; D014867:Water / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D011522:Protons; D014867:Water