title: Fix L, a haemoglobin that acts as an oxygen sensor: signalling mechanism and structural basis of its homology with PAS domains.
abstract: Fix L, which contains a haemoglobin domain homologous to the PAS family and a histidine kinase domain, forms, with Fix J, a two-component signalling complex that regulates expression of nitrogenase genes in Rhizobium. Spin transitions of its haem iron trigger stereochemical changes in and around the haem that, together with steric effects, control the activity of the kinase. Homology with the PAS family is based on a common core of about 20 structurally equivalent sites from which polar residues are excluded.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, CB2 2QH, UK.
authors.forename: M F
authors.initials: MF
authors.lastname: Perutz
authors.forename: M
authors.initials: M
authors.lastname: Paoli
authors.forename: A M
authors.initials: AM
authors.lastname: Lesk
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D015374:Biosensing Techniques; D006420:Hemeproteins / Q000737:chemistry* / Q000378:metabolism*; D006454:Hemoglobins / Q000737:chemistry / Q000378:metabolism; D000071677:Histidine Kinase; D006801:Humans; D008958:Models, Molecular; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism; D010108:Oxyhemoglobins / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012231:Rhizobium / Q000502:physiology*; D015398:Signal Transduction; D014907:Whales
chemical_list: D001426:Bacterial Proteins; D006420:Hemeproteins; D006454:Hemoglobins; D009211:Myoglobin; D010108:Oxyhemoglobins; C067929:FixL protein, Bacteria; D000071677:Histidine Kinase