## Abstract The spatial dependence of the ring‐current magnetic anisotropy of nucleic acid bases is presented in a series of graphs in cylindrical coordinates. The curves may be used to calculate the ring‐current shift at a point in a cylinder of radius 10Å extending 8 Å above and below each ring o
Calibration of ring-current effects in proteins and nucleic acids
✍ Scribed by David A. Case
- Publisher
- Springer Netherlands
- Year
- 1995
- Tongue
- English
- Weight
- 619 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0925-2738
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✦ Synopsis
Density functional chemical shielding calculations are reported for methane molecules placed in a variety of positions near aromatic rings of the type found in proteins and nucleic acids. The results are compared to empirical formulas that relate these intermolecular shielding effects to magnetic anisotropy ('ring-current') effects and to electrostatic polarization of the C-H bonds. Good agreement is found between the empirical formulas and the quantum chemistry results, allowing a reassessment of the ringcurrent intensity factors for aromatic amino acids and nucleic acid bases. Electrostatic interactions contribute significantly to the computed chemical shift dispersion. Prospects for using this information in the analysis of chemical shifts in proteins and nucleic acids are discussed.
📜 SIMILAR VOLUMES
## Abstract | I. | Introduction | 306 | | II. | Supramolecular Structure Characterization | 308 | | | A. A Protein Is Used as a “Hook” | 309 | | | 1. Immuno‐Precipitation | 309 | | | 2. Tagging with a Poly‐Histidine Sequence | 310 | | | 3. Direct Analysis of Large Protein Complexes | 3