title: Heme-based sensors in biological systems.
abstract: The past several years have been witness to a staggering rate of advancement in the understanding of how organisms respond to changes in the availability of diatomic molecules that are toxic and/or crucial to survival. Heme-based sensors presently constitute the majority of the proteins known to sense NO, O2 and CO and to initiate the chemistry required to adapt to changes in their availabilities. Knowledge of the three characterized members of this class, soluble guanylate cyclase, FixL and CooA, has grown substantially during the past year. The major advances have resulted from a broad range of approaches to elucidation of both function and mechanism. They include growth in the understanding of the interplay between the heme and protein in soluble guanylate cyclase, as well as alternate means for its stimulation. Insight into the O2-induced structural changes in FixL has been supplied by the single crystal structure of the heme domain of Bradyrhizobium japonicum. Finally, the ligation environment and ligand interchange that facilitates CO sensing by CooA has been established by spectroscopic and mutagenesis techniques.
authors.affiliation: Department of Chemistry, Ladd Hall, North Dakota State University, Fargo, ND 58105-5516, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Rodgers
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D001692:Biological Transport; D015374:Biosensing Techniques; D002248:Carbon Monoxide / Q000494:pharmacology; D004789:Enzyme Activation; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006418:Heme / Q000737:chemistry / Q000378:metabolism*; D006420:Hemeproteins / Q000378:metabolism; D000071677:Histidine Kinase; D009569:Nitric Oxide / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; C088904:CooA protein, E coli; D029968:Escherichia coli Proteins; D006420:Hemeproteins; D036781:Fimbriae Proteins; D009569:Nitric Oxide; D006418:Heme; D002248:Carbon Monoxide; C067929:FixL protein, Bacteria; D000071677:Histidine Kinase; D006162:Guanylate Cyclase; D010100:Oxygen