title: Structural studies on the 2.25-MDa homomultimeric phosphoenolpyruvate synthase from Staphylothermus marinus.
abstract: The phosphoenolpyruvate synthase of the hyperthermophilic archaeon Staphylothermus marinus forms an unusually large homomultimeric complex of 93 kDa subunits. Electron image analysis of negatively stained and low-dose unstained preparations showed that the complex has a single, stable characteristic view and a well-preserved core with threefold rotational symmetry. The periphery of the assembly is composed of a nebulous, possibly flexible, component. Mass measurements by scanning transmission electron microscopy yielded a molecular weight of 2250 +/- 230 kDa, confirming the well-defined nature of the structure and indicating that it is composed of 24 +/- 2.5 subunits. The stability and symmetry of the characteristic projection views suggest a polyhedral three-dimensional architecture. The novel quaternary arrangement of this enzyme might be a consequence of its adaptation to an extreme environment.
authors.affiliation: Abteilung Molekulare Strukturbiologie, Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, Martinsried bei München, D-82152, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Harauz
authors.forename: C
authors.initials: C
authors.lastname: Cicicopol
authors.forename: R
authors.initials: R
authors.lastname: Hegerl
authors.forename: Z
authors.initials: Z
authors.lastname: Cejka
authors.forename: K
authors.initials: K
authors.lastname: Goldie
authors.forename: U
authors.initials: U
authors.lastname: Santarius
authors.forename: A
authors.initials: A
authors.lastname: Engel
authors.forename: W
authors.initials: W
authors.lastname: Baumeister
mesh_terms: D001105:Archaea / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000648:ultrastructure*; D019143:Evolution, Molecular; D006358:Hot Temperature; D007091:Image Processing, Computer-Assisted; D017348:Microscopy, Electron, Scanning Transmission; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000737:chemistry / Q000648:ultrastructure*; D017866:Phosphotransferases (Paired Acceptors) / Q000737:chemistry / Q000648:ultrastructure*; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D017866:Phosphotransferases (Paired Acceptors); C022509:pyruvate, water dikinase