Institute of Genetics - University of Cologne
Section of Molecular Genetics
Protein-DNA and Protein-Protein Interactions
Section Head: Benno Müller-Hill
Research and three recent publications
Before my retirement in February 1998 we had analysed the function of seven transcription
factors: LacR, GalR, TrpR, AraC and Lambda R of E.coli and GCN4 of yeast. After my retirement
we concentrated on LacR and Lambda R. These proteins have like many other proteins modular structure.
Thus, their DNA binding domains are well separated from their aggregation domains. Dimers react with DNA targets
of dyadic symmetry.
It was our goal to understand as well as possible the functions and interactions
of these six proteins with their modular partners.
>From our publications of this time period I choose the following three as the most interesting ones:
1.Révet et al. Current Biol. 9,151-154 (1999). Lambda repressor is at physiological concentrations a dimer.
Only at very high concentrations it aggregates into a tetramer or an octamer. Such tetramers are also formed when
two dimers of Lambda repressor are bound to two lambda operators which are 24bp apart: two such tetramers from then an octamer.
Since the DNA bound tetramers are unique in the cell they form octamers over large distances.
2. Spott et al. J.Mol.Biol. 296,673-684 (2000). A single amino acid substitution of LacR, D278L, changes the specifity of dimerisation.
3. Pereg-Gerk et al. J.Mol.Biol. 299,805-812 (2000). A single amino acid substitution, K84L, increases the thermostability of LacR by 40°C.
Collaborations with other institutes
Jeffrey Miller, University of California, Los Angeles, CA, USA
Bernard Révet, Institut Gustave Rousse, Villesuif, France
Wolfram Neiss, Anatomy, University of Cologne, Germany
We gratefully acknowledge financial support by the following agencies or
sponsors: Deutsche Forschungsgemeinschaft through SFB 274 ; through
Normalverfahren Mu 575/10-12. The general support of Fonds der Chemie and the ground support of the Land Nordrhein-Westfalen
are gratefully acknowledged.