4o99

Crystal structure of Beta-ketothiolase (PhaA) from Ralstonia eutropha H16

spinqualitylabelsall models 4o99, resolution 1.96Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4o99 is a 4 chain structure with sequence from Cupriavidus necator H16. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.96Å Ligands: GOL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function THIL_CUPNH Catalyzes the condensation of two acetyl-coA units to form acetoacetyl-CoA. Is involved in the biosynthesis of polyhydroxybutyrate (PHB), which is accumulated as an intracellular energy reserve material when cells grow under conditions of nutrient limitation. Also catalyzes the reverse reaction, i.e. the cleavage of acetoacetyl-CoA, and is therefore also involved in the reutilization of PHB. Publication Abstract from PubMed PhaA from Ralstonia eutropha (RePhaA) is the first enzyme in the polyhydroxyalbutyrate (PHB) biosynthetic pathway and catalyzes the condensation of two molecules of acetyl-CoA to acetoacetyl-CoA. To investigate the molecular mechanism underlying PHB biosynthesis, we determined the crystal structures of the RePhaA protein in apo- and CoA-bound forms. The RePhaA structure adopts the type II biosynthetic thiolase fold forming a tetramer by means of dimerization of two dimers. The crystal structure of RePhaA in complex with CoA revealed that the enzyme contained a unique Phe219 residue, resulting that the ADP moiety binds in somewhat different position compared with that bound in other thiolase enzymes. Our study provides structural insight into the substrate specificity of RePhaA. Results indicate the presence of a small pocket near the Cys88 covalent catalytic residue leading to the possibility of the enzyme to accommodate acetyl-CoA as a sole substrate instead of larger acyl-CoA molecules such as propionyl-CoA. Furthermore, the roles of key residues involved in substrate binding and enzyme catalysis were confirmed by site-directed mutagenesis. Crystal structure and biochemical characterization of PhaA from Ralstonia eutropha, a polyhydroxyalkanoate-producing bacterium.,Kim EJ, Kim KJ Biochem Biophys Res Commun. 2014 Sep 12;452(1):124-9. doi:, 10.1016/j.bbrc.2014.08.074. Epub 2014 Aug 21. PMID:25152395 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thiolase 3D structures

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