title: Class III adenylyl cyclases: molecular mechanisms of catalysis and regulation.
abstract: Class III adenylyl cyclases are the most abundant type of cyclic AMP-producing enzymes. The adjustment of the cellular levels of this second messenger is achieved by a variety of regulatory mechanisms which couple signals to adenylyl cyclase activity. Because of the divergent nature of stimuli which impinge on these enzymes, highly individualized class III adenylyl cyclases have evolved in metazoans, eukaryotic unicells and bacteria. Regulation usually exploits the dimeric structure of the catalyst, whose active centres form at the dimer interface. The fold of the catalytic domains and the basic catalytic mechanisms are similar in all class III adenylyl cyclases, and substrate binding generally closes the active site by an induced-fit mechanism. Regulatory inputs can result in dramatic rearrangements of the catalytic domains within the dimer, which often are based on rotational movements.
authors.affiliation: Abteilung Pharmazeutische Biochemie, Fakultät für Chemie und Pharmazie, Universität Tübingen, 72076 Tübingen, Germany. juergen.linder@uni-tuebingen.de
authors.forename: J U
authors.initials: JU
authors.lastname: Linder
mesh_terms: D000262:Adenylyl Cyclases / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002384:Catalysis; D020134:Catalytic Domain; D002462:Cell Membrane / Q000201:enzymology; D000242:Cyclic AMP / Q000378:metabolism*; D019281:Dimerization; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D007527:Isoenzymes; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; C421784:adenylate cyclase 3