Ultra-high resolution 17O solid-state NMR spectroscopy of biomolecules: A comprehensive spectral analysis of monosodium L-glutamate·monohydrate

Wong, Alan; Howes, A. P.; Yates, Jonathan R.; Watts, Anthony; Anupõld, Tiit; Past, Jaan; Samoson, Ago; Dupree, R.; Smith, Mark E.

doi:10.1039/c1cp20629j

Cited by 31 publications

(36 citation statements)

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“…While there have been a number of experimental solid-state 17 O NMR and computational studies on the 17 O QC and CS tensors in carboxylic acids and their salts, [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] none of the previous studies have dealt with a carboxylate (-COO − ) group bound to Pt(II). The primary goals of the present study are (i) to experimentally determine the 17 O CS and QC tensors in these important Pt(II) anticancer drugs and (ii) to examine the effect of bonding to a transition metal on these 17 O NMR tensors.…”

Section: Introductionmentioning

confidence: 98%

A solid-state¹⁷O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

et al. 2015

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We report synthesis and solid-state NMR characterization of two 17 O-labeled platinum anticancer drugs: cis-diammine(1,1-cyclobutane-[ 17 O 4 ]dicarboxylato)platinum(II) (carboplatin) and ([ 17 O 4 ]oxalato)[(1R, 2R)-(−)-1,2-cyclohexanediamine)]platinum(II) (oxaliplatin). Both 17 O chemical shift (CS) and quadrupolar coupling (QC) tensors were measured for the carboxylate groups in these two compounds. With the aid of plane wave DFT computations, the 17 O CS and QC tensor orientations were determined in the molecular frame of reference. Significant changes in the 17 O CS and QC tensors were observed for the carboxylate oxygen atom upon its coordination to Pt(II). In particular, the 17 O isotropic chemical shifts for the oxygen atoms directly bonded to Pt(II) are found to be smaller (more shielded) by 200 ppm than those for the non-Pt-coordinated oxygen atoms within the same carboxylate group. Examination of the 17 O CS tensor components reveals that such a large 17 O coordination shift is primarily due to the shielding increase along the direction that is within the O=C-O-Pt plane and perpendicular to the O-Pt bond. This result is interpreted as due to the donation from the oxygen nonbonding orbital (electron lone pair) to the Pt(II) empty d yz orbital, which results in large energy gaps between (Pt-O) and unoccupied molecular orbitals, thus reducing the paramagnetic shielding contribution along the direction perpendicular to the O-Pt bond. We found that the 17 O QC tensor of the carboxylate oxygen is also sensitive to Pt(II) coordination, and that 17 O CS and QC tensors provide complementary information about the O-Pt bonding.

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Section: Introductionmentioning

confidence: 98%

A solid-state¹⁷O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

et al. 2015

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“…31,32 Thus, although there are a number of promising MQMAS studies of 17 O-labeled biological samples, the experimental results are limited by signal-to-noise and therefore require long acquisition times. 33–42 …”

Section: Introductionmentioning

confidence: 99%

Structural Insights into Bound Water in Crystalline Amino Acids: Experimental and Theoretical ¹⁷O NMR

et al. 2015

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Direct 17O NMR structural studies of bound water in crystalline hydrates and biological macromolecules are challenging due to the low natural abundance and quadrupolar nature of 17O nuclei. However, the advent of high field NMR positions 17O NMR to become an important tool to address structural problems in biological solids. We show herein that the NMR properties of 17O in a series of amino acids and dipeptides can be determined by a combination of non-spinning and magic-angle spinning experiments using a range of magnetic field strengths from 9.4 to 21.1 T. Furthermore, we propose a 17O chemical shift fingerprint region for bound water molecules in biological solids that is well outside the previously determined ranges for carbonyl, carboxylic, and hydroxyl oxygens, thereby offering the ability to resolve multiple 17O environments using rapid one-dimensional NMR techniques. Finally, we compare our experimental data against quantum chemical calculations using GIPAW and hybrid-DFT, finding intriguing discrepancies between the electric field gradients calculated from structures determined by x-ray and neutron diffraction.

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“…35, 36 Thus, although there are a number of exciting MQMAS studies of 17 O labeled biological samples, the experimental results are clearly limited by signal-to-noise, hence requiring long acquisition times. 37–46 …”

Section: Introductionmentioning

confidence: 99%

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization

et al. 2013

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Dynamic nuclear polarization of 17O was studied using four different polarizing agents – the biradical TOTAPOL, and the monoradicals trityl and SA-BDPA, as well as a mixture of the latter two. Field profiles, DNP mechanisms and enhancements were measured to better understand and optimize directly polarizing this low-gamma quadrupolar nucleus using both mono- and bi-radical polarizing agents. Enhancements were recorded < 88 K and were > 100 using the trityl (OX063) radical and < 10 with the other polarizing agents. The > 10,000 fold savings in acquisition time enabled a series of biologically relevant small molecules to be studied with small sample sizes and the measurement of various quadrupolar parameters. The results are discussed with comparison to room temperature studies and GIPAW quantum chemical calculations. These experimental results illustrate the strength of high field DNP and the importance of radical selection for studying low-gamma nuclei.

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Ultra-high resolution 17O solid-state NMR spectroscopy of biomolecules: A comprehensive spectral analysis of monosodium L-glutamate·monohydrate

Cited by 31 publications

References 50 publications

A solid-state¹⁷O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

A solid-state¹⁷O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

Structural Insights into Bound Water in Crystalline Amino Acids: Experimental and Theoretical ¹⁷O NMR

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization

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Ultra-high resolution 17O solid-state NMR spectroscopy of biomolecules: A comprehensive spectral analysis of monosodium L-glutamate·monohydrate

Cited by 31 publications

References 50 publications

A solid-state17O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

A solid-state17O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

Structural Insights into Bound Water in Crystalline Amino Acids: Experimental and Theoretical 17O NMR

Dynamic Nuclear Polarization of 17O: Direct Polarization

Contact Info

Product

Resources

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A solid-state¹⁷O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

A solid-state¹⁷O NMR study of platinum-carboxylate complexes: carboplatin and oxaliplatin

Structural Insights into Bound Water in Crystalline Amino Acids: Experimental and Theoretical ¹⁷O NMR

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization