Exposed tyrosine residues of lambda cro repressor protein evidenced by nitration and photo CIDNP experiments.
The tyrosine residues of lambda cro repressor were partially nitrated with tetranitromethane under mild conditions. After digestion by Achromobacter protease I, the extent of nitration was determined by HPLC and amino acid analysis. Tyr 26 was most easily nitrated and Tyr 51 followed it. Tyr 10 was resistant to nitration. By comparison of the proton magnetic resonance spectrum of the partially nitrated cro protein with the above result, the aromatic proton resonances of the tyrosine side chains could be assigned to individual tyrosine residues. The extent of nitration is parallel to the accessibility to a flavin dye as measured by photo CIDNP (chemically induced dynamic nuclear polarization).
D000596:Amino Acids / Q000032:analysis; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008697:Methane / Q000031:analogs & derivatives*; D010446:Peptide Fragments / Q000032:analysis; D010777:Photochemistry; D012097:Repressor Proteins / Q000378:metabolism*; D013774:Tetranitromethane / Q000494:pharmacology*; D014157:Transcription Factors / Q000378:metabolism*; D014443:Tyrosine / Q000032:analysis*; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
D000596:Amino Acids; D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D014443:Tyrosine; D013774:Tetranitromethane; D008697:Methane