title: A spring-loaded release mechanism regulates domain movement and catalysis in phosphoglycerate kinase.
abstract: Phosphoglycerate kinase (PGK) is the enzyme responsible for the first ATP-generating step of glycolysis and has been implicated extensively in oncogenesis and its development. Solution small angle x-ray scattering (SAXS) data, in combination with crystal structures of the enzyme in complex with substrate and product analogues, reveal a new conformation for the resting state of the enzyme and demonstrate the role of substrate binding in the preparation of the enzyme for domain closure. Comparison of the x-ray scattering curves of the enzyme in different states with crystal structures has allowed the complete reaction cycle to be resolved both structurally and temporally. The enzyme appears to spend most of its time in a fully open conformation with short periods of closure and catalysis, thereby allowing the rapid diffusion of substrates and products in and out of the binding sites. Analysis of the open apoenzyme structure, defined through deformable elastic network refinement against the SAXS data, suggests that interactions in a mostly buried hydrophobic region may favor the open conformation. This patch is exposed on domain closure, making the open conformation more thermodynamically stable. Ionic interactions act to maintain the closed conformation to allow catalysis. The short time PGK spends in the closed conformation and its strong tendency to rest in an open conformation imply a spring-loaded release mechanism to regulate domain movement, catalysis, and efficient product release.
authors.affiliation: Structural Biology Group, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France.
authors.forename: Louiza
authors.initials: L
authors.lastname: Zerrad
authors.forename: Angelo
authors.initials: A
authors.lastname: Merli
authors.forename: Gunnar F
authors.initials: GF
authors.lastname: Schröder
authors.forename: Andrea
authors.initials: A
authors.lastname: Varga
authors.forename: Éva
authors.initials: É
authors.lastname: Gráczer
authors.forename: Petra
authors.initials: P
authors.lastname: Pernot
authors.forename: Adam
authors.initials: A
authors.lastname: Round
authors.forename: Mária
authors.initials: M
authors.lastname: Vas
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Bowler
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001703:Biophysics / Q000379:methods; D002384:Catalysis; D018360:Crystallography, X-Ray / Q000379:methods; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010735:Phosphoglycerate Kinase / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012542:Scattering, Radiation; D017386:Sequence Homology, Amino Acid; D013816:Thermodynamics
chemical_list: D000255:Adenosine Triphosphate; D010735:Phosphoglycerate Kinase