Heme acquisition by hemophores
| Autor: | Cescau, F, Cwerman, C, Létoffé, S., Delepelaire, P., Wandersman, C., Biville, F., Cescau, S., Cwerman, H. |
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| Přispěvatelé: | Génétique et biochimie des microorganismes (GBM), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Institut de biochimie et génétique cellulaires (IBGC), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Models
Molecular MESH: Signal Transduction Hemeprotein Operon Protein Conformation Receptors Cell Surface MESH: Carrier Proteins MESH: Escherichia coli Proteins Heme Biology General Biochemistry Genetics and Molecular Biology Biomaterials 03 medical and health sciences chemistry.chemical_compound Protein structure MESH: Protein Conformation Bacterial Proteins [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology MESH: Bacterial Proteins 030304 developmental biology MESH: Receptors Cell Surface 0303 health sciences 030306 microbiology Chemiosmosis Escherichia coli Proteins Metals and Alloys Membrane Proteins Heme transport Cell biology Biochemistry chemistry MESH: Heme bacteria MESH: Membrane Proteins Signal transduction General Agricultural and Biological Sciences Bacterial outer membrane Carrier Proteins MESH: Models Molecular Signal Transduction |
| Zdroj: | BioMetals BioMetals, 2007, 20 (3-4), pp.603-613. ⟨10.1007/s10534-006-9050-y⟩ BioMetals, Springer Verlag, 2007, 20 (3-4), pp.603-613. ⟨10.1007/s10534-006-9050-y⟩ |
| ISSN: | 0966-0844 1572-8773 |
| DOI: | 10.1007/s10534-006-9050-y⟩ |
| Popis: | International audience; Bacterial hemophores are secreted to the extracellular medium, where they scavenge heme from various hemoproteins due to their higher affinity for this compound, and return it to their specific outer membrane receptor. HasR, the outer membrane receptor of the HasA hemophore, assumes multiple functions which require various energy levels. Binding of heme and, of heme-free or heme-loaded hemophores is energy-independent. Heme transfer from the holo-hemophore to the outer membrane receptor is also energy-independent. In contrast, heme transport and hemophore release require basal or high levels of TonB and proton motive force, respectively. In addition, HasR is a component of a signaling cascade, regulating expression of the has operon via specific sigma and anti-sigma factors encoded by genes clustered at the has operon. The signal is the heme landing on HasR in the presence of the hemophore in its apo form. The has system is the only system thus far characterized in which the anti-sigma factor is submitted to the same signaling cascade as the target operon. Specific autoregulation of the has system, combined with negative regulation by the Fur protein, permits bacterial adaptation to the available iron source. In the presence of a heme-loaded hemophore, inactive anti-sigma factor is accumulated and can be activated as soon as the heme source dries up. Hence, the has system, instead of being submitted to amplification like other systems regulated by sigma anti-sigma factors, functions by pulses triggered by heme availability. |
| Databáze: | OpenAIRE |
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