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Updated: May 28, 2026

PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase
09:31

PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase

Published on: September 26, 2020

700GHzでEPRによって明らかにされたトリプトファンラジカルの水素結合

Stefan Stoll1, Hannah S Shafaat, J Krzystek

  • 1Department of Chemistry, University of California Davis, Davis, California 95616, United States. stst@uw.edu

Journal of the American Chemical Society
|October 20, 2011
PubMed
まとめ

レドックス活性トリプトファンは,生物学的電子移転において重要な役割を果たします. この研究では,高度なEPRスペクトロスコーピーを用いて,水素結合がタンパク質の酸化還元化学において極めて重要なトリプトファンラジカルにどのように影響するかを示した.

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Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals01:17

Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals

Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
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IR Spectrum Peak Broadening: Hydrogen Bonding

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However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular hydrogen bonding...
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A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
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¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

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¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

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Proton (¹H) NMR: Chemical Shift

Organic molecules primarily contain carbon and hydrogen atoms. While all the hydrogen isotopes are NMR-active, protium or hydrogen-1 is the most abundant. It has a significant energy separation between its nuclear spin states due to its large gyromagnetic ratio. As per Boltzmann's distribution, an increase in the energy separation implies a greater excess population of nuclei available for excitation, resulting in a strong NMR absorption signal.
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