Genetic Assignment of Resonances in the NMR Spectrum of a Protein: Lac Repressor

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 78; no. 5; pp. 2707 - 2711
• Main Authors: Mary Ann C. Jarema, Lu, Ponzy, Miller, Jeffrey H.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01-05-1981; National Acad Sciences
• Subjects: Amino acids; Amino Acids - analysis; Biochemistry; Chemical equilibrium; DNA; Escherichia coli - genetics; Fluorine; Genes, Regulator; Genetic mutation; Hydrogen-Ion Concentration; Line spectra; Magnetic Resonance Spectroscopy; Mutation; Proteins; Protons; Repressor proteins; Repressor Proteins - genetics; Transcription Factors - genetics; Tyrosine - analysis
• DOI: 10.1073/pnas.78.5.2707
• EISSN: 1091-6490
• ISSN: 0027-8424

By using a systematic genetic approach, the resonances in the19F NMR spectrum of 3-fluorotyrosine-substituted lac repressor protein have been assigned. The NMR data indicate that each monomer of the repressor consists of two distinct and independent domains. One domain, the NH2-terminal sixth of the primary sequence, which has been shown to be very important for DNA binding, is very mobile. The remaining COOH-terminal sequence is more rigid. Ligands of the repressor, which affect its DNA binding capability, lead to conformational changes in the COOH-terminal domain. The approach to the assignment of spectral features taken here can be extended to other systems.