We propose to crystallize and to determine the three-dimensional structure of procaryotic transcription factors and proteins that are interacting with these regulators, that control their activity and couple this control to metabolic signal transduction chains. The first protein is bAes from E. coli. It is an enzyme with acetyl esterase activity that exhibits homology to the family of hormone-sensitive lipases. The interest in this enzyme is based on its demonstrated interaction with MaIT, the central regulator of the E. coli maltose system.pThe second transcription regulator is bMIc, a global transcriptional repressor controlling the expression of the malt gene and in addition of a number of genes encoding some specific (for glucose and mannose) and all general enzymes of the E. coli phosphotransferase system (PTS). The interest in MIc comes from its unusual mode of inactivation by sequestration to the PtsG transporter. We plan to determine the structure of MIc as well as of the complex of MIc with the soluble EIIB domain of PtsG.pThe third transcription regulator is bTrmB, a sugar-specific transcription repressor controlling the genes encoding a high affinity and binding protein-dependent ABC transporter for trehalose and maltose in the hyperthermophilic arechaeon Thermococcus litoralis. The interest in this regulator comes from the fact that it is the first identified sugar specific regulator of archaea acting on a transcription machinery of eukaryotic relateness.pThe goal of this proposal is aimed at the understanding of a novel type of transcriptional regulation in which the regulator is controlled by direct protein-protein interaction.
