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Study of complexes of a tryptophan‐free mutant of E. coli trp aporepressor with tryptophan analogues using optically detected magnetic resonance (ODMR)
Author(s) -
Ozarowski Andrzej,
Wu Jie Qiang,
Maki August H
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)01602-5
Subject(s) - tryptophan , chemistry , mutant , escherichia coli , resonance (particle physics) , stereochemistry , phosphorescence , trp operon , crystallography , biochemistry , fluorescence , amino acid , lac operon , physics , particle physics , quantum mechanics , gene
Phosphorescence and optically detected magnetic resonance (ODMR) spectra of tryptophan (W) and several of its analogues (4‐, 5‐, 6‐methyltryptophan (MeW); 4‐, 5‐, 6‐fluorotryptophan (FW); 5‐bromotryptophan) are compared with those of complexes formed with the W‐free trp aporepressor from Escherichia coli (W19,99F). W19,99F binds W and each analogue except 4‐FW with an estimated K D ≤30 μM; triplet state spectroscopic and kinetic effects that accompany binding at the corepressor site are reported. ODMR data for the MeW isomers are presented for the first time. No binding of 7‐azaW is observed, in agreement with the low affinity found by previous workers.