This model represents the class II subfamily of poly(R)-hydroxyalkanoate synthases, which polymerizes hydroxyacyl-CoAs, typically with six to fourteen carbons in the hydroxyacyl backbone into aliphatic esters termed poly(R)-hydroxyalkanoic acids. These polymers accumulate as carbon and energy storage inclusions in many species and can amount to 90 percent of the dry weight of cell. [Fatty acid and phospholipid metabolism, Biosynthesis]