title: Structure of the CO sensing transcription activator CooA.
abstract: CooA is a homodimeric transcription factor that belongs to the catabolite activator protein (CAP) family. Binding of CO to the heme groups of CooA leads to the transcription of genes involved in CO oxidation in Rhodospirillum rubrum. The 2.6 A structure of reduced (Fe2+) CooA reveals that His 77 in both subunits provides one heme ligand while the N-terminal nitrogen of Pro 2 from the opposite subunit provides the other ligand. A structural comparison of CooA in the absence of effector and DNA (off state) with that of CAP in the effector and DNA bound state (on state) leads to a plausible model for the mechanism of allosteric control in this class of proteins as well as the CO dependent activation of CooA.
authors.affiliation: Departments of Molecular Biology and Biochemistry and Physiology and Biophysics and the Program in Macromolecular Structure, University of California, Irvine, California 92697-3900, USA.
authors.forename: W N
authors.initials: WN
authors.lastname: Lanzilotta
authors.forename: D J
authors.initials: DJ
authors.lastname: Schuller
authors.forename: M V
authors.initials: MV
authors.lastname: Thorsteinsson
authors.forename: R L
authors.initials: RL
authors.lastname: Kerby
authors.forename: G P
authors.initials: GP
authors.lastname: Roberts
authors.forename: T L
authors.initials: TL
authors.lastname: Poulos
mesh_terms: D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D006418:Heme / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; C088904:CooA protein, E coli; D029968:Escherichia coli Proteins; D008024:Ligands; D036781:Fimbriae Proteins; D006418:Heme