Polyketide synthesis cyclase (IPR006765)

Short name: Polyketide_synth_cyclase

Overlapping homologous superfamilies

Family relationships



Aromatic polyketides are assembled by a type II (iterative) polyketide synthases (PKSs) in bacteria. Type II PKS complexes consist of several monofunctional or bifunctional proteins which produce polyketide chains of variable but defined length from a specific starter unit and a number of extender units. They also specify the initial regiospecific folding and cyclization pattern of nascent polyketides either through the action of a cyclase (CYC) subunit or through the combined action of site-specific ketoreductase and CYC subunits [PMID: 9224566, PMID: 19903160].

This family represents a number of cyclases involved in polyketide synthesis in a number of actinobacterial species.

Tetracenomycin F2 cyclase (TcmI) catalyses an aromatic rearrangement in the biosynthetic pathaway of tetracenomycin C from Streptomyces glaucescens. The protein is a homodimer where each subunit forms a beta-alpha-beta fold belonging to the ferrodoxin fold superfamily [PMID: 15231835]. Four strands of antiparallel sheets and a layer of alpha helices create a cavity which was proposed to be the active site. This structure shows strong topological similarity to a polyketide monoxygenase (Q53908) from S. coelicolor which functions in the actinorhodin biosynthesic pathway [PMID: 12514126]. It was suggested, therefore, that this fold is well suited to serve as a framework for rearrangements and chemical modification of polyaromatic substrates.

GO terms

Biological Process

GO:0030639 polyketide biosynthetic process

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.