TY - JOUR
T1 - Solution NMR of polypeptides hyperpolarized by dynamic nuclear polarization
AU - Ragavan, Mukundan
AU - Chen, Hsueh Ying
AU - Sekar, Giridhar
AU - Hilty, Christian
PY - 2011/8/1
Y1 - 2011/8/1
N2 - Hyperpolarization of nuclear spins through techniques such as dynamic nuclear polarization (DNP) can greatly increase the signal-to-noise ratio in NMR measurements, thus eliminating the need for signal averaging. This enables the study of many dynamic processes which would otherwise not be amenable to study by NMR spectroscopy. A report of solid-to liquid-state DNP of a short peptide, bacitracin A, as well as of a full-length protein, L23, is presented here. The polypeptides are hyperpolarized at low temperature and dissolved for NMR signal acquisition in the liquid state in mixtures of organic solvent and water. Signal enhancements of 300-2000 are obtained in partially deuterated polypeptide when hyperpolarized on 13C and of 30-180 when hyperpolarized on 1H. A simulated spectrum is used to identify different resonances in the hyperpolarized 13C spectra, and the relation between observed signal enhancement for various groups in the protein and relaxation parameters measured from the hyperpolarized samples is discussed. Thus far, solid-to liquid-state DNP has been used in conjunction with small molecules. The results presented here, however, demonstrate the feasibility of hyperpolarizing larger proteins, with potential applications toward the study of protein folding or macromolecular interactions.
AB - Hyperpolarization of nuclear spins through techniques such as dynamic nuclear polarization (DNP) can greatly increase the signal-to-noise ratio in NMR measurements, thus eliminating the need for signal averaging. This enables the study of many dynamic processes which would otherwise not be amenable to study by NMR spectroscopy. A report of solid-to liquid-state DNP of a short peptide, bacitracin A, as well as of a full-length protein, L23, is presented here. The polypeptides are hyperpolarized at low temperature and dissolved for NMR signal acquisition in the liquid state in mixtures of organic solvent and water. Signal enhancements of 300-2000 are obtained in partially deuterated polypeptide when hyperpolarized on 13C and of 30-180 when hyperpolarized on 1H. A simulated spectrum is used to identify different resonances in the hyperpolarized 13C spectra, and the relation between observed signal enhancement for various groups in the protein and relaxation parameters measured from the hyperpolarized samples is discussed. Thus far, solid-to liquid-state DNP has been used in conjunction with small molecules. The results presented here, however, demonstrate the feasibility of hyperpolarizing larger proteins, with potential applications toward the study of protein folding or macromolecular interactions.
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U2 - 10.1021/ac201122k
DO - 10.1021/ac201122k
M3 - Article
C2 - 21651293
AN - SCOPUS:79961011529
SN - 0003-2700
VL - 83
SP - 6054
EP - 6059
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 15
ER -