A Solid-State <sup>17</sup>O NMR Study of <scp>l</scp>-Tyrosine in Different Ionization States: Implications for Probing Tyrosine Side Chains in Proteins

Zhu, Jianfeng; Lau, Justin Y. C.; Wu, Gang

doi:10.1021/jp1055123

Cited by 40 publications

(33 citation statements)

References 84 publications

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“…GIPAW calculations and NMR experiments of the crystalline solid (non-DNP) at higher magnetic fields (Table 2, Figure S4) agree well with experimental parameters as well as other phenolic-like systems studied previously. 100, 140 …”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization

et al. 2013

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“…A similar "␦ 11 -␦ 22 crossover" effect was previously reported for the phenolic oxygen atom of tyrosine between the protonated and deprotonated states. 64 To further identify the origin of the observed 17 O coordination shift in terms of specific molecular orbitals (MOs), we performed a detailed magnetic shielding analysis using the ADF program. 46 According to the Ramsey formalism of nuclear magnetic shielding, 65 the total magnetic shielding at a nucleus can be divided into diamagnetic and paramagnetic contributions:…”

Section: The Origin Of 17 O Coordination Shiftsmentioning

confidence: 99%

“…56,57,64,67 that the high-lying nonbonding orbitals (electron lone pairs) on the oxygen atom often make the largest paramagnetic shielding contribution. Use oxaliplatin as an example.…”

Section: The Origin Of 17 O Coordination Shiftsmentioning

confidence: 99%

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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“…The paramagnetic term, on the other hand, gives rise to the anisotropic components of shielding and originates from the interaction between the ground and excited state wavefunctions. Previous reports have demonstrated that the paramagnetic shielding of carbon- and nitrogen- bound 17 O nuclei originates from oxygen lone pair electrons that occupy high-energy orbitals [46–49]. However, the orientation of the largest component of chemical shift tensor along the V-O bond in HS003 indicates the participation of vanadium orbitals in the paramagnetic shielding of the peroxido oxygens.…”

Section: Resultsmentioning

confidence: 99%

Direct detection and characterization of bioinorganic peroxo moieties in a vanadium complex by 17O solid-state NMR and density functional theory

Gupta

Stringer²,

Struppe

et al. 2018

Solid State Nuclear Magnetic Resonance

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Electronic and structural properties of short-lived metal-peroxido complexes, which are key intermediates in many enzymatic reactions, are not fully understood. While detected in various enzymes, their catalytic properties remain elusive because of their transient nature, making them difficult to study spectroscopically. We integrated 17O solid-state NMR and density functional theory (DFT) to directly detect and characterize the peroxido ligand in a bioinorganic V(V) complex mimicking intermediates non-heme vanadium haloperoxidases. 17O chemical shift and quadrupolar tensors, measured by solid-state NMR spectroscopy, probe the electronic structure of the peroxido ligand and its interaction with the metal. DFT analysis reveals the unusually large chemical shift anisotropy arising from the metal orbitals contributing towards the magnetic shielding of the ligand. The results illustrate the power of an integrated approach for studies of oxygen centers in enzyme reaction intermediates.

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A Solid-State ¹⁷O NMR Study of l-Tyrosine in Different Ionization States: Implications for Probing Tyrosine Side Chains in Proteins

Cited by 40 publications

References 84 publications

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization

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

Direct detection and characterization of bioinorganic peroxo moieties in a vanadium complex by 17O solid-state NMR and density functional theory

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A Solid-State 17O NMR Study of l-Tyrosine in Different Ionization States: Implications for Probing Tyrosine Side Chains in Proteins

Cited by 40 publications

References 84 publications

Dynamic Nuclear Polarization of 17O: Direct Polarization

Dynamic Nuclear Polarization of 17O: Direct Polarization

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

Direct detection and characterization of bioinorganic peroxo moieties in a vanadium complex by 17O solid-state NMR and density functional theory

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A Solid-State ¹⁷O NMR Study of l-Tyrosine in Different Ionization States: Implications for Probing Tyrosine Side Chains in Proteins

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization

Dynamic Nuclear Polarization of ¹⁷O: Direct Polarization

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