title: Striking conformational change suspected within the phosphoribulokinase dimer induced by interaction with GAPDH.
abstract: A multitechnique approach was used to study the [glyceraldehyde-3-phosphate dehydrogenase](2 x 4)-[phosphoribulokinase](2 x 2) multienzymatic complex of the alga Chlamydomonas reinhardtii. On the one hand, each component of the complex was compared with known atomic structures of related enzymes or of similar enzymes originating from different organisms. On the other hand, the overall low resolution architecture of the whole complex was studied using cryoelectron microscopy and image processing techniques. The dimers of phosphoribulokinase are suspected to undergo a dramatic change in activity during a cycle of binding and detaching from tetramers of glyceraldehyde-3-phosphate dehydrogenase. This is likely supported by strong structural differences between the modeled phosphoribulokinase dimers and the counterpart in the three-dimensional reconstruction volume of the whole complex obtained from cryoelectron microscope images.
authors.affiliation: Laboratoire de Minéralogie Cristallographie Paris, CNRS, UMR-7590, Universités Paris 6 et Paris 7, Case 115, 4 Place Jussieu, 75252 Paris Cedex 05, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Mouche
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gontero
authors.forename: Isabelle
authors.initials: I
authors.lastname: Callebaut
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Mornon
authors.forename: Nicolas
authors.initials: N
authors.lastname: Boisset
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016825:Chlamydomonas reinhardtii; D020285:Cryoelectron Microscopy; D019281:Dimerization; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure*; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D046911:Macromolecular Substances; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D017853:Phosphotransferases (Alcohol Group Acceptor); C022390:phosphoribulokinase