Open AccessNMR studies of the trp repressor from Escherichia coli
Author(s) -
LANE Andrew N.,
JARDETZKY Oleg
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb09210.x
Subject(s) - chemistry , chemical shift , homonuclear molecule , residue (chemistry) , nuclear magnetic resonance spectroscopy , nuclear overhauser effect , histidine , lac repressor , spectroscopy , valine , stereochemistry , nuclear magnetic resonance , escherichia coli , crystallography , amino acid , organic chemistry , molecule , biochemistry , physics , lac operon , quantum mechanics , gene
High‐resolution proton nuclear magnetic resonance spectra of the trp repressor of Escherichia coli under various conditions are reported and analysed. The spectrum of the denatured state agrees with that predicted from the amino acid composition, with the exception of the two histidine residues, which have different chemical shifts although they titrate normally. The spectrum of the native protein shows the presence of extensive secondary and tertiary structure. Using information from chemical shifts, number of protons, titration behaviour, homonuclear chemical‐shift‐correlated spectroscopy and nuclear Overhauser enhancement correlated spectroscopy, most of the aromatic protons have been assigned to residue type. Further, about 30% of the aliphatic protons have been assigned to residue type two‐dimensional spectroscopy. Nuclear Overhauser enhancements establish that high‐field methyl groups belonging to a valine residue lie directly over an aromatic ring.