Poster abstracts
Poster number 97 submitted by Christian ONeil
Dynamic nuclear polarization of GB1 protein by co-crystallization with partial doping
Christian M. ONeil (Biophysics Graduate Program), Dan W. Conroy (Ohio State Chemistry Department), Lakshmi Bhai (Ohio State Physics Department)
Abstract:
Large biomolecules, such as amyloids, crystals, and DNA-protein complexes, are difficult to study by ordinary NMR methods. Magic angle spinning advancements have allowed solid-state NMR (SSNMR) to become a leading technique in collecting structural and dynamics data of these samples. The inherent low sensitivity of NMR has led to the development of dynamic nuclear polarization (DNP), which can improve the signal to noise of SSNMR experiments to drastically reduce the length of time needed to collect this data. One of the necessary components of DNP is the inclusion of a biradical which is usually dissolved with the protein crystal in “DNP juice” (1:3:6 H2O, D2O, and deuterated glycerol). Here, we show that up to four times signal enhancement by DNP could be obtained by co-crystallization of native GB1 with GB1 K28C Q32C tagged with two MTSL radicals while maintaining the crystalline form of the sample. This enhancement is seen at a radical concentration as low as 5 mM, nearly half the amount used in DNP juice. Additionally, the relaxation times of these samples are faster than those doped with more traditional biradicals further increasing the potential efficiency of this doping technique. By using a stronger biradical, the signal to noise enhancement could improve to allow this method of doping to be used on other crystals and even amyloid proteins in the future.
Keywords: NMR, DNP, GB1