Crystal structure of Ralstonia eutropha polyhydroxyalkanoate synthase C-terminal domain and reaction mechanisms.
Polyhydroxyalkanoates (PHAs) are natural polyesters synthesized by numerous microorganisms as energy and reducing power storage materials, and have attracted much attention as substitutes for petroleum-based plastics. Here, we report the first crystal structure of Ralstonia eutropha PHA synthase at 1.8 Å resolution and structure-based mechanisms for PHA polymerization. RePhaC1 contains two distinct domains, the N-terminal (RePhaC1ND ) and C-terminal domains (RePhaC1CD ), and exists as a dimer. RePhaC1CD catalyzes polymerization via non-processive ping-pong mechanism using a Cys-His-Asp catalytic triad. Molecular docking simulation of 3-hydroxybutyryl-CoA to the active site of RePhaC1CD reveals residues involved in the formation of 3-hydroxybutyryl-CoA binding pocket and substrate binding tunnel. Comparative analysis with other polymerases elucidates how different classes of PHA synthases show different substrate specificities. Furthermore, we attempted structure-based protein engineering and developed a RePhaC1 mutant with enhanced PHA synthase activity.
['Kim|Jieun|J|', 'Kim|Yeo-Jin|YJ|', 'Choi|So Young|SY|', 'Lee|Sang Yup|SY|', 'Kim|Kyung-Jin|KJ|']
D000214:Acyl Coenzyme A D000217:Acyltransferases D020134:Catalytic Domain D002942:Circular Dichroism D018360:Crystallography, X-Ray D020118:Cupriavidus necator D008958:Models, Molecular D062105:Molecular Docking Simulation D016296:Mutagenesis D000072417:Protein Domains D013050:Spectrometry, Fluorescence D013379:Substrate Specificity
Crystal structure Ralstonia eutropha Polyhydroxyalkanoates PHA synthase Enzyme mechanism