title: Unravelling the shape and structural assembly of the photosynthetic GAPDH-CP12-PRK complex from Arabidopsis thaliana by small-angle X-ray scattering analysis.
abstract: Oxygenic photosynthetic organisms produce sugars through the Calvin-Benson cycle, a metabolism that is tightly linked to the light reactions of photosynthesis and is regulated by different mechanisms, including the formation of protein complexes. Two enzymes of the cycle, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK), form a supramolecular complex with the regulatory protein CP12 with the formula (GAPDH-CP122-PRK)2, in which both enzyme activities are transiently inhibited during the night. Small-angle X-ray scattering analysis performed on both the GAPDH-CP12-PRK complex and its components, GAPDH-CP12 and PRK, from Arabidopsis thaliana showed that (i) PRK has an elongated, bent and screwed shape, (ii) the oxidized N-terminal region of CP12 that is not embedded in the GAPDH-CP12 complex prefers a compact conformation and (iii) the interaction of PRK with the N-terminal region of CP12 favours the approach of two GAPDH tetramers. The interaction between the GAPDH tetramers may contribute to the overall stabilization of the GAPDH-CP12-PRK complex, the structure of which is presented here for the first time.
authors.affiliation: Department of Chemistry, University of Rome `Sapienza', Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Del Giudice
authors.affiliation: Department of Chemistry, University of Rome `Sapienza', Rome, Italy.
authors.forename: Nicolae Viorel
authors.initials: NV
authors.lastname: Pavel
authors.affiliation: Department of Chemistry, University of Rome `Sapienza', Rome, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Galantini
authors.affiliation: Department of Chemistry `G. Ciamician', University of Bologna, Bologna, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Falini
authors.affiliation: Department of Pharmacy and Biotechnology - FaBiT, University of Bologna, Bologna, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Trost
authors.affiliation: Department of Chemistry `G. Ciamician', University of Bologna, Bologna, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Fermani
authors.affiliation: Department of Pharmacy and Biotechnology - FaBiT, University of Bologna, Bologna, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Sparla
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis / Q000235:genetics*; D011485:Protein Binding; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D053838:Scattering, Small Angle; D016415:Sequence Alignment; D014961:X-Ray Diffraction
chemical_list: D029681:Arabidopsis Proteins; C533605:CP12-1 protein, Arabidopsis; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011994:Recombinant Proteins; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); D017853:Phosphotransferases (Alcohol Group Acceptor); C022390:phosphoribulokinase
keywords: Arabidopsis thaliana; Calvin–Benson cycle; SAXS; multiprotein complex