Morphological change in cellular granule formation of poly[(R)-3-hydroxybutyrate] caused by DNA-binding-related mutations of an autoregulated repressor PhaR.

PhaP is a major poly[(R)-3-hydroxybutyrate] [P(3HB)]-granule-associated protein. Its gene expression is controlled by an autoregulated repressor, PhaR, in Paracoccus denitrificans. The packing force of the P(3HB) granule by PhaP is greatly influenced by the number of PhaP molecules.

Autoregulator protein PhaR for biosynthesis of polyhydroxybutyrate [P(3HB)] possibly has two separate domains that bind to the target DNA and P(3HB): Functional mapping of amino acid residues responsible for DNA binding.

PhaR from Paracoccus denitrificans functions as a repressor or autoregulator of the expression of genes encoding phasin protein (PhaP) and PhaR itself, both of which are components of polyhydroxyalkanoate (PHA) granules (A. Maehara, S. Taguchi, T.