chalconesynthaselike

Chalcone synthase-like (CHS-like) refers to a family of small, type III polyketide synthases homologous to chalcone synthase (CHS). CHS-like enzymes catalyze iterative condensations of malonyl-CoA with a starter CoA ester to form polyketide products that serve as precursors to flavonoids and related phenylpropanoid metabolites. The enzymes are typically around 40 kDa per subunit and function as homodimers, with a conserved catalytic core responsible for the decarboxylative condensations that build the carbon skeleton.

Biochemical properties and products vary among CHS-like enzymes. The reaction usually begins with a starter CoA, commonly p-coumaroyl-CoA, and proceeds through three malonyl-CoA extensions. Depending on the enzyme and starter substrate, the same chemistry can yield different final products: CHS generates chalcones such as naringenin chalcone, stilbene synthases (STS) produce stilbenes like resveratrol, and other CHS-like enzymes, such as benzalacetone synthase (BAS), yield distinct polyketides. Substrate flexibility and subtle active-site differences drive the diversity of products, including bibenzyls and related compounds.

Distribution and roles: CHS-like enzymes are widespread in plants, contributing to the biosynthesis of flavonoids, anthocyanins, and phytoalexins, thereby influencing pigmentation, UV protection, and defense responses. Gene duplications and divergent evolution have generated a broad CHS-like repertoire across plant lineages, with expression patterns that respond to developmental cues and environmental stress.

Applications and significance: CHS-like enzymes are central tools in plant metabolic engineering and biotechnology. Their substrate promiscuity and ability to produce a range of bioactive polyketides make them targets for efforts to synthesize flavonoids, stilbenes, and related compounds in heterologous hosts for research, pharmaceutical, and nutraceutical applications.