PMID: 16803881 , Related PDB ids: 2H6B, 2H6C
Joyce MG, Levy C, Gabor K, Pop SM, Biehl BD, Doukov TI, Ryter JM, Mazon H, Smidt H, van den Heuvel RH, Ragsdale SW, van der Oost J, Leys D
CprK crystal structures reveal mechanism for transcriptional control of halorespiration.
J Biol Chem. 2006 Sep 22;281(38):28318-25. Epub 2006 Jun 27.
Halorespiration is a bacterial respiratory process in which haloorganic compounds act as terminal electron acceptors. This process is controlled at transcriptional level by CprK, a member of the ubiquitous CRP-FNR family. Here we present the crystal structures of oxidized CprK in presence of the ligand ortho-chlorophenolacetic acid and of reduced CprK in absence of this ligand. These structures reveal that highly specific binding of chlorinated, rather than the corresponding non-chlorinated, phenolic compounds in the NH(2)-terminal beta-barrels causes reorientation of these domains with respect to the central alpha-helix at the dimer interface. Unexpectedly, the COOH-terminal DNA-binding domains dimerize in the non-DNA binding state. We postulate the ligand-induced conformational change allows formation of interdomain contacts that disrupt the DNA domain dimer interface and leads to repositioning of the helix-turn-helix motifs. These structures provide a structural framework for further studies on transcriptional control by CRP-FNR homologs in general and of halorespiration regulation by CprK in particular.