Biomolecular DNP-Supported NMR Spectroscopy using Site-Directed Spin Labeling
Résumé
Dynamic nuclear polarization (DNP) has been
shown to greatly enhance spectroscopic sensitivity, creating
novel opportunities for NMR studies on complex and large
molecular assemblies in life and material sciences. In such
applications, however, site-specificity and spectroscopic resolution
become critical factors that are usually difficult to control
by current DNP-based approaches. We have examined
in detail the effect of directly attaching mono- or biradicals
to induce local paramagnetic relaxation effects and, at the
same time, to produce sizable DNP enhancements. Using
a membrane-embedded ion channel as an example, we
varied the degree of paramagnetic labeling and the location
of the DNP probes. Our results show that the creation of
local spin clusters can generate sizable DNP enhancements
while preserving the intrinsic benefits of paramagnetic relaxation
enhancement (PRE)-based NMR approaches. DNP
using chemical labeling may hence provide an attractive
route to introduce molecular specificity into DNP studies in
life science applications and beyond.