title: lac Repressor: a proton magnetic resonance look at the deoxyribonucleic acid binding fragment.
abstract: The DNA binding fragment from Escherichia coli lac repressor, the N-terminal 56 amino acid residue "headpiece", has been examined by high-resolution 1H NMR spectroscopy at 360 MHz. The aromatic region has been examined in detail along with the four headpieces of altered repressors that are each missing one of the tyrosines, respectively. The spectra here show more resolved resonances and correct errors in the resonance assignments that have been published by Ribeiro et al. (1981b) Ribeiro, A. A., Wemmer, D., Bray, R. P., Wade-Jardetzky, N. G., & Jardetzky, O. (1981) Biochemistry 20, 818-823]. These corrections allow an interpretation of the spectroscopic observations that is now consistent with the extensive genetic analysis that has been carried out with the lac repressor gene. In addition, nuclear Overhauser enhancement measurements give a guide to the interresidue distances among the aromatic residues in this protein fragment.
mesh_terms: D004247:DNA; D004926:Escherichia coli / Q000378:metabolism*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000378:metabolism*; D013696:Temperature; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D012097:Repressor Proteins; D014157:Transcription Factors; D004247:DNA