Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Solid-state 17 O NMR of amino acids
AU - Pike, K.J.
AU - Lemaitre, V.
AU - Kukol, A.
AU - Anupõld, T.
AU - Samoson, A.
AU - Howes, A.P.
AU - Watts, A.
AU - Smith, M.E.
AU - Dupree, R.
PY - 2004
Y1 - 2004
N2 - 17 O solid-state NMR from 14 amino acids is reported here, greatly increasing the number investigated. In most cases well-separated resonances from carbonyl and hydroxyl oxygens with distinct second-order quadrupolar line shapes are observed using a 600 MHz spectrometer with fast magic angle spinning (MAS). This is in contrast to the motionally averaged resonances usually seen from amino acids in solution. For amino acids double-angle rotation (DOR) produces a decrease in the line width by more than a factor of 40, providing very high resolution, ∼ 1 ppm, spectra. The oxygen lines in alanine and the carbonyl oxygens in L-glutamic acid hydrochloride are assigned using 1H-decoupled DOR. The NMR interaction parameters for amino acids show a wide variation of XQ, from 6.4 to 8.6 MHz, η from 0.0 to 0.9, and δiso from 83 to 353 ppm. The high quality of the MAS NMR line shapes obtained at 14.1 T means that even small changes in parameters can be very accurately deduced, offering the possibility of 17O NMR as a sensitive probe of structural changes in these and related compounds. The D- and L-forms of glutamic acid hydrochloride are shown to have the same NMR parameters to within error, which are very different from those reported in the literature for the D,L-form. A strong correlation (∼-1200 ppm/Å) is found between δiso and the C-O bond length of the carbonyl oxygens. On the basis of these data, enriching specific amino acids in more complex polypeptides and proteins could provide site-selective information about the bonding and functionality of different sites in biomolecules. An estimate is made of the possible detection limit for such species.
AB - 17 O solid-state NMR from 14 amino acids is reported here, greatly increasing the number investigated. In most cases well-separated resonances from carbonyl and hydroxyl oxygens with distinct second-order quadrupolar line shapes are observed using a 600 MHz spectrometer with fast magic angle spinning (MAS). This is in contrast to the motionally averaged resonances usually seen from amino acids in solution. For amino acids double-angle rotation (DOR) produces a decrease in the line width by more than a factor of 40, providing very high resolution, ∼ 1 ppm, spectra. The oxygen lines in alanine and the carbonyl oxygens in L-glutamic acid hydrochloride are assigned using 1H-decoupled DOR. The NMR interaction parameters for amino acids show a wide variation of XQ, from 6.4 to 8.6 MHz, η from 0.0 to 0.9, and δiso from 83 to 353 ppm. The high quality of the MAS NMR line shapes obtained at 14.1 T means that even small changes in parameters can be very accurately deduced, offering the possibility of 17O NMR as a sensitive probe of structural changes in these and related compounds. The D- and L-forms of glutamic acid hydrochloride are shown to have the same NMR parameters to within error, which are very different from those reported in the literature for the D,L-form. A strong correlation (∼-1200 ppm/Å) is found between δiso and the C-O bond length of the carbonyl oxygens. On the basis of these data, enriching specific amino acids in more complex polypeptides and proteins could provide site-selective information about the bonding and functionality of different sites in biomolecules. An estimate is made of the possible detection limit for such species.
KW - Carboxylic acids
KW - Chemical bonds
KW - Correlation methods
KW - Hydrochloric acid
KW - Nuclear magnetic resonance
KW - Resonance
KW - Solutions
KW - Double-angle rotation (DOR)
KW - Dynamic angle spinning (DAS)
KW - Magic angle spinning (MAS)
KW - Amino acids
U2 - 10.1021/jp049958x
DO - 10.1021/jp049958x
M3 - Journal article
VL - 108
SP - 9256
EP - 9263
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 26
ER -