Abstract
Because arginine residues in proteins are expected to be in their protonated form almost without exception, reports demonstrating that a protein arginine residue is charge-neutral are rare and potentially controversial. Herein, we present a C-13-detected NMR experiment for probing individual arginine residues in proteins notwithstanding the presence of chemical and conformational exchange effects. In the experiment, the N-15(eta) and N-15(epsilon) chemical shifts of an arginine head group are correlated with that of the directly attached C-13(zeta). In the resulting spectrum, the number of protons in the arginine head group can be obtained directly from the N-15-H-1 scalar coupling splitting pattern. We applied this method to unambiguously determine the ionization state of the R52 side chain in the photoactive yellow protein from Halorhodospira halophila. Although only three H-eta atoms were previously identified by neutron crystallography, we show that R52 is predominantly protonated in solution.
Original language | English |
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Pages (from-to) | 239-242 |
Number of pages | 4 |
Journal | Angewandte Chemie-International Edition |
Volume | 56 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2-Jan-2017 |
Keywords
- arginine
- cross polarization
- N-15-H-1 spin-spin coupling
- NMR spectroscopy
- photoactive yellow protein
- PHOTOACTIVE YELLOW PROTEIN
- INTRINSICALLY DISORDERED PROTEINS
- SIDE-CHAIN DYNAMICS
- HYDROGEN-BONDS
- ACTIVE-SITE
- N-15
- RESIDUES
- LYSINE
- BACTERIORHODOPSIN
- THERMOSTABILITY