Differentiation of the binding of two ligands to a tetrameric protein with a single symmetric active site by ¹⁹ F NMR.

ABSTRACT: R67 dihydrofolate reductase (R67 DHFR) is a plasmid-encoded enzyme that confers resistance to the antibacterial drug trimethoprim. R67 DHFR is a tetramer with a single active site that is unusual as both cofactor and substrate are recognized by symmetry-related residues. Such promiscuity has limited our previous efforts to differentiate ligand binding by NMR. To address this problem, we incorporated fluorine at positions 4, 5, 6, or 7 of the indole rings of tryptophans 38 and 45 and characterized the spectra to determine which probe was optimal for studying ligand binding. Two resonances were observed for all apo proteins. Unexpectedly, the W45 resonance appeared broad, and truncation of the disordered N-termini resulted in the appearance of one sharp W45 resonance. These results are consi

SUBMITTER: Fuente-Gomez GJ 

PROVIDER: S-EPMC7784773 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature