Polyhydroxybutyrate (PHB) is a biocompatible and biodegradable polymer that has the potential to replace fossil-derived polymers. The enzymes involved in the biosynthesis of PHB are β-ketothiolase (PhaA), acetoacetyl-CoA reductase (PhaB), and PHA synthase (PhaC). PhaC in
Arthrospira platensis is the key enzyme for
[...] Read more.
Polyhydroxybutyrate (PHB) is a biocompatible and biodegradable polymer that has the potential to replace fossil-derived polymers. The enzymes involved in the biosynthesis of PHB are β-ketothiolase (PhaA), acetoacetyl-CoA reductase (PhaB), and PHA synthase (PhaC). PhaC in
Arthrospira platensis is the key enzyme for PHB production. In this study, the recombinant
E. cloni ®10G cells harboring
A. platensis phaC (rPhaC
Ap) was constructed. The overexpressed and purified rPhaC
Ap with a predicted molecular mass of 69 kDa exhibited
Vmax,
Km, and
kcat values of 24.5 ± 2 μmol/min/mg, 31.3 ± 2 µM and 412.7 ± 2 1/s, respectively. The catalytically active rPhaC
Ap was a homodimer. The three-dimensional structural model for the asymmetric PhaC
Ap homodimer was constructed based on
Chromobacterium sp. USM2 PhaC (PhaC
Cs). The obtained model of PhaC
Ap revealed that the overall fold of one monomer was in the closed, catalytically inactive conformation whereas the other monomer was in the catalytically active, open conformation. In the active conformation, the catalytic triad residues (Cys151-Asp310-His339) were involved in the binding of substrate 3HB-CoA and the CAP domain of PhaC
Ap involved in the dimerization.
Full article
