Open AccessPhotochemically induced dynamic nuclear polarization investigation of complex formation of the NH2-terminal DNA-binding domain of lac repressor with poly[d(AT)].
Author(s) -
Friedrich Buck,
Heinz Rüterjans,
Robert Kaptein,
Konrad Beyreuther
Publication year - 1980
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.77.9.5145
Subject(s) - cidnp , repressor , lac repressor , dna , chemistry , histidine , biophysics , stereochemistry , polarization (electrochemistry) , crystallography , biochemistry , lac operon , biology , enzyme , transcription factor , plasmid , gene
The interaction of the NH2-terminal DNA-binding domain of lac repressor with synthetic oligo[d(AT)] was studied by a photo-CIDNP technique (CIDNP is chemically induced dynamic nuclear polarization). Three of the four tyrosines of the NH2-terminal region were found to be accessible to the photosensitive dye. The corresponding ring proton resonances were enhanced in the photo-CIDNP 1H NMR spectrum, and the only histidine (histidine 29) was located at the surface of the domain, which is supposed to be linked to the core protein of lac repressor by a flexible hinge region. After complex formation of the NH2-terminal region with oligo[d(AT)], two of the three tyrosine residues were no longer accessible to solvent or to photosensitive dye, which is strong evidence that the two tyrosines are part of the contact region.