title: Structural and biochemical characterization of fructose-1,6/sedoheptulose-1,7-bisphosphatase from the cyanobacterium Synechocystis strain 6803.
abstract: Cyanobacterial fructose-1,6/sedoheptulose-1,7-bisphosphatase (cy-FBP/SBPase) plays a vital role in gluconeogenesis and in the photosynthetic carbon reduction pathway, and is thus a potential enzymatic target for inhibition of harmful cyanobacterial blooms. Here, we describe the crystal structure of cy-FBP/SBPase in complex with AMP and fructose-1,6-bisphosphate (FBP). The allosteric inhibitor AMP and the substrate FBP exhibit an unusual binding mode when in complex with cy-FBP/SBPase. Binding mode analysis suggested that AMP bound to the allosteric sites near the interface across the up/down subunit pairs C1C4 and C2C3 in the center of the tetramer, while FBP binds opposite to the interface between the horizontal subunit pairs C1C2 or C3C4. We identified a series of residues important for FBP and AMP binding, and suggest formation of a disulfide linkage between Cys75 and Cys99. Further analysis indicates that cy-FBP/SBPase may be regulated through ligand binding and alteration of the structure of the enzyme complex. The interactions between ligands and cy-FBP/SBPase are different from those of ligand-bound structures of other FBPase family members, and thus provide new insight into the molecular mechanisms of structure and catalysis of cy-FBP/SBPase. Our studies provide insight into the evolution of this enzyme family, and may help in the design of inhibitors aimed at preventing toxic cyanobacterial blooms.
authors.affiliation: Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education, and College of Chemistry, Central China Normal University, Wuhan, 430079, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Feng
authors.forename: Yao
authors.initials: Y
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Deng
authors.forename: Ding
authors.initials: D
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wan
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Wang
authors.forename: Weiwei
authors.initials: W
authors.lastname: Wang
authors.forename: Xun
authors.initials: X
authors.lastname: Liao
authors.forename: Yanliang
authors.initials: Y
authors.lastname: Ren
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Hu
mesh_terms: D000249:Adenosine Monophosphate / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D000494:Allosteric Regulation; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D055162:Biocatalysis; D002942:Circular Dichroism; D006597:Fructose-Bisphosphatase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005635:Fructosediphosphates / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D046939:Synechocystis / Q000201:enzymology*; D014961:X-Ray Diffraction
chemical_list: D001426:Bacterial Proteins; D005635:Fructosediphosphates; D008024:Ligands; D050505:Mutant Proteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D000249:Adenosine Monophosphate; D006597:Fructose-Bisphosphatase; D010744:Phosphoric Monoester Hydrolases; C022627:sedoheptulose-bisphosphatase; C029063:fructose-1,6-diphosphate
keywords: biochemical characterization; cyanobacteria; fructose-1,6/sedoheptulose-1,7-bisphosphatase, site-directed mutagenesis; structure