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Characterization of the flavin–protein interaction in L ‐Lactate oxidase and old yellow enzyme by resonance inverse Raman spectroscopy
Author(s) -
Bienstock Rachelle J.,
Schopfer Lawrence M.,
Morris Michael D.
Publication year - 1987
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250180403
Subject(s) - flavin group , chemistry , resonance raman spectroscopy , raman spectroscopy , hydrogen bond , ligand (biochemistry) , stereochemistry , crystallography , photochemistry , enzyme , biochemistry , organic chemistry , physics , receptor , molecule , optics
Abstract Resonance inverse Raman spectroscopy was used to examine the interactions between the flavin and surounding protein in L ‐lactate oxidase (from Mycobacterium smegmatis ) and Old Yellow Enzyme (from brewer's bottom yeast). Spectra were taken of the enzymes both free and bound to various ligands. For L ‐lactate oxidase, the ligands consisted of substrate analogs (acetate, propionate) and inorganic anions (phosphate, sulfate and nitrate). For the inorganic anions, the expected attenuation with detuning was not observed for several bands which are associated with flavin rings II and III. This effect appears to be due to a disruption of ring stacking between the uracil–pyrazine end of the flavin moiety and an aromatic amino acid. A shift in the 1232 cm −1 band and changes in the bandwidths of bands in the 1450–1600 cm −1 region indicate minor reorganization of the hydrogen bonding structure around the isoalloxazine on ligand binding. For Old Yellow Enzyme, the ligand was chloride. Chloride caused a slight change to the Raman spectrum, indicative of decreased hydrogen bonding to the flavin.