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High‐resolution NMR of exchangeable protons in arginine, oligoarginines, and the arginine‐rich histone tetramer
Author(s) -
Klavan Leonard,
Crothers Donald M.
Publication year - 1979
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1979.360180502
Subject(s) - chemistry , tetramer , arginine , crystallography , side chain , protonation , nuclear magnetic resonance spectroscopy , proton , molecule , proton nmr , stereochemistry , computational chemistry , amino acid , ion , biochemistry , organic chemistry , enzyme , physics , quantum mechanics , polymer
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.