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CATH Superfamily 3.40.47.10

Thiolase/Chalcone synthase

The name of this superfamily has been modified since the most recent official CATH+ release (v4_3_0). At the point of the last release, this superfamily was: waiting to be named.

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 19: Polyketide synthase type I

There are 7 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Beta-ketoacyl-[acyl-carrier-protein] synthase I. [EC: 2.3.1.41]
Acyl-[acyl-carrier-protein] + malonyl-[acyl-carrier-protein] = 3-oxoacyl- [acyl-carrier-protein] + CO(2) + [acyl-carrier-protein].
  • Responsible for the chain-elongation step of dissociated (type II) fatty-acid biosynthesis, i.e. the addition of two C atoms to the fatty-acid chain.
  • Escherichia coli mutants that lack this enzyme are deficient in unsaturated fatty acids.
  • Can use fatty acyl thioesters of ACP (C(2) to C(16)) as substrates, as well as fatty acyl thioesters of Co-A (C(4) to C(16)).
  • The substrate specificity is very similar to that of EC 2.3.1.179 with the exception that the latter enzyme is far more active with palmitoleoyl-ACP (C(16)-Delta(9)) as substrate, allowing the organism to regulate its fatty-acid composition with changes in temperature.
 92 A0A0E7SMM4 A0A0E7SMM4 A0A0E7SMM4 A0A0E7SMM4 A0A0E7SMM4 A0A0E7SMM4 A0A0E8NTV0 A0A0E8NTV0 A0A0E8NTV0 A0A0E8NTV0
(82 more...)
Mycolipanoate synthase. [EC: 2.3.1.252]
A long-chain acyl-CoA + 3 (S)-methylmalonyl-CoA + 6 NADPH + holo- [mycolipanoate synthase] = mycolipanoyl-[mycolipanoate synthase] + 4 CoA + 3 CO(2) + 6 NADP(+) + 3 H(2)O.
  • This mycobacterial enzyme accepts long-chain fatty acyl groups from their CoA esters and extends them by incorporation of three methylmalonyl (but not malonyl) residues, forming trimethyl-branched fatty-acids such as (2S,4S,6S)-2,4,6-trimethyl-tetracosanoate (C(27)- mycolipanoate).
  • Since the enzyme lacks a thioesterase domain, the product remains bound to the enzyme and requires additional enzyme(s) for removal.
 16 A0A089QRB9 A0A089QRB9 A0A089QRB9 A0A089QRB9 A0A0E8NV99 A0A0E8NV99 A0A0E8NV99 A0A0E8NV99 A0A0H3L8P3 A0A0H3L8P3
(6 more...)
Narbonolide synthase. [EC: 2.3.1.240]
Malonyl-CoA + 6 (2S)-methylmalonyl-CoA + 5 NADPH = narbonolide + 7 CoA + 7 CO(2) + 5 NADP(+) + 2 H(2)O.
  • The product, narbonolide, contains a 14-membered ring and is an intermediate in the biosynthesis of narbonomycin and pikromycin in the bacterium Streptomyces venezuelae.
  • The enzyme also produces 10-deoxymethynolide (see EC 2.3.1.239).
  • The enzyme has 29 active sites arranged in four polypeptides (pikAI - pikAIV) with a loading domain, six extension modules and a terminal thioesterase domain.
  • Each extension module contains a ketosynthase (KS), keto reductase (KR), an acyltransferase (AT) and an acyl-carrier protein (ACP).
  • Not all active sites are used in the biosynthesis.
 7 Q9ZGI2 Q9ZGI3 Q9ZGI4 Q9ZGI4 Q9ZGI5 Q9ZGI5 Q9ZGI5
10-deoxymethynolide syntase. [EC: 2.3.1.239]
Malonyl-CoA + 5 (2S)-methylmalonyl-CoA + 5 NADPH = 10-deoxymethynolide + 6 CoA + 6 CO(2) + 5 NADP(+) + 2 H(2)O.
  • The product, 10-deoxymethynolide, contains a 12-membered ring and is an intermediate in the biosynthesis of methymycin in the bacterium Streptomyces venezuelae.
  • The enzyme also produces narbonolide (see EC 2.3.1.240).
  • The enzyme has 29 active sites arranged in four polypeptides (pikAI - pikAIV) with a loading domain, six extension modules and a terminal thioesterase domain.
  • Each extension module contains a ketosynthase (KS), keto reductase (KR), an acyltransferase (AT) and an acyl-carrier protein (ACP).
  • Not all active sites are used in the biosynthesis.
 7 Q9ZGI2 Q9ZGI3 Q9ZGI4 Q9ZGI4 Q9ZGI5 Q9ZGI5 Q9ZGI5
6-deoxyerythronolide-B synthase. [EC: 2.3.1.94]
Propanoyl-CoA + 6 (2S)-methylmalonyl-CoA + 6 NADPH = 6-deoxyerythronolide B + 7 CoA + 6 CO(2) + H(2)O + 6 NADP(+).
  • The product, 6-deoxyerythronolide B, contains a 14-membered lactone ring and is an intermediate in the biosynthesis of erythromycin antibiotics.
  • Biosynthesis of 6-deoxyerythronolide B requires 28 active sites that are precisely arranged along three large polypeptides, denoted DEBS1, -2 and -3.
  • The polyketide product is synthesized by the processive action of a loading didomain, six extension modules and a terminal thioesterase domain.
  • Each extension module contains a minimum of a ketosynthase (KS), an acyltransferase (AT) and an acyl-carrier protein (ACP).
  • The KS domain both accepts the growing polyketide chain from the previous module and catalyzes the subsequent decarboxylative condensation between this substrate and an ACP-bound methylmalonyl extender unit, introduce by the AT domain.
  • This combined effort gives rise to a new polyketide intermediate that has been extended by two carbon atoms.
 6 Q03131 Q03131 Q03132 Q03132 Q03133 Q03133
Mycocerosate synthase. [EC: 2.3.1.111]
(1) A long-chain acyl-[mycocerosic acid synthase] + 3 methylmalonyl-CoA + 6 NADPH = a trimethylated-mycocerosoyl-[mycocerosate synthase] + 3 CoA + 3 CO(2) + 6 NADP(+) + 3 H(2)O. (2) A long-chain acyl-[mycocerosate synthase] + 4 methylmalonyl-CoA + 8 NADPH = a tetramethylated-mycocerosoyl-[mycocerosate synthase] + 4 CoA + 4 CO(2) + 8 NADP(+) + 4 H(2)O.
  • The enzyme, characterized from mycobacteria, is loaded with a long- chain acyl moiety by EC 6.2.1.49 and elongates it by incorporation of three or four methylmalonyl (but not malonyl) residues, to form tri- or tetramethyl-branched fatty-acids, respectively, such as 2,4,6,8- tetramethyloctacosanoate (C(32)-mycocerosate).
  • Since the enzyme lacks a thioesterase domain, the product remains bound and requires additional enzyme(s) for removal.
  • Even though the enzyme can accept C(6) to C(20) substrates in vitro, it prefers to act on C(14)-C(20) substrates in vivo.
 4 A0A0H3MGR2 A0A0H3MGR2 Q02251 Q02251
Lovastatin nonaketide synthase. [EC: 2.3.1.161]
9 malonyl-CoA + 11 NADPH + S-adenosyl-L-methionine + holo-[lovastatin nonaketide synthase] = dihydromonacolin L-[lovastatin nonaketide synthase] + 9 CoA + 9 CO(2) + 11 NADP(+) + S-adenosyl-L-homocysteine + 6 H(2)O.
  • This fungal enzyme system comprises a multi-functional polyketide synthase (PKS) and an enoyl reductase.
  • The PKS catalyzes many of the chain building reactions of EC 2.3.1.85, as well as a reductive methylation and a Diels-Alder reaction, while the reductase is responsible for three enoyl reductions that are necessary for dihydromonacolin L acid production.
 2 Q0C8M3 Q9Y8A5