High-resolution NMR of exchangeable protons in arginine, oligoarginines, and the arginine-rich histone tetramer
✍ Scribed by Leonard Klavan; Donald M. Crothers
- Book ID
- 102762919
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1979
- Tongue
- English
- Weight
- 694 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
High‐resolution nmr of exchangeable protons in the side chain of arginine reveals two distinct resonances arising from restricted rotation about the N(1)–C(ε) bond. Spectral assignments based upon pH‐dependent proton‐exchange behaviour identified each resonance as arising from one of the magnetically distinct guanidinium amino groups in the molecule. Computer simulation of the temperature‐dependent coalescence of these peaks defines an activation energy of 14.3 kcal/mol for internal rotation about this bond. Similar results to those observed in monoarginine are reported for diarginine, triarginine, and the arginine‐rich histone tetramer. Based on these findings, a nonsymmetric mode of arginine–ligand interaction is suggested, and the molecular dynamics of proton exchange in the arginine side chain is discussed.