A direct photo-activated affinity modification of tetracycline transcription repressor protein TetR(D) with tetracycline

Results of a first successful application of a direct photo-induced affinit y modification of Tet repressor (TetR(D)) protein with tetracycline within a complex of known three-dimensional structure are described. The condition s of the modification have provided suitable yields of the modified complex and allowed characterization of the modified segments of the protein. The potential of tetracycline as a fine modifying reagent was established. In t he complex of TetR(D) protein with tetracycline, the antibiotic modifies at least two segments, Ile59-Glu73 and Ala173-Glu183, which form a binding tu nnel for the drug according to the X-ray analysis, These data open possibil ities for the use of different tetracycline targets for structural studies in solution. (C) 2000 Federation of European Biochemical Societies. Publish ed by Elsevier Science B.V. All rights reserved.