Assignment of Proton Amide Resonances of T4 Lysozyme by ¹³C and ¹⁵N Multiple Isotopic Labeling

The unambiguous resolution and assignment of resonances from specific protons is the major limitation in 1H NMR studies of proteins.1Heteronuclear double-resonance spectroscopy of samples labeled with stable isotopes such as 13C and l5N offers one solution to the problem.2-4 This methodology has been used to identify the signals from specific imino protons in transfer RNA and amide protons in peptides. When introduced into proteins, a heteroatomic label can be used to edit a complex proton NMR spectrum into a subset of resonances from a particular functional group.5, 6 We have observed the peaks from the amide protons of the five phenylalanines in T4 lysozyme labeled with (15N)-phenylalanine but could not assign the signals to specific amino acids based solely on the chemical shifts. © 1986, American Chemical Society. All rights reserved.

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Author Terrence Gilbert Oas Biochemistry