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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_2_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 51914: 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
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.
 20 A0A0N0N0K5 A0A0N0N0K5 A0A0N0N6L5 A0A0N0N6L5 A0A0N0N6Y5 A0A0N0N6Y5 A0A0N1G573 A0A0N1G573 A0A0N1H1Z6 A0A0N1H1Z6
(10 more...)
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.
 6 A0A0U5LZ52 A0A0U5LZ52 A0A0U5M1E2 A0A0U5M1E2 X7YFR4 X7YFR4
Mycocerosate synthase. [EC: 2.3.1.111]
(1) A long-chain acyl-CoA + 3 methylmalonyl-CoA + 6 NADPH + a holo- [mycocerosate synthase] = a trimethylated-mycocerosoyl-[mycocerosate synthase] + 4 CoA + 3 CO(2) + 6 NADP(+) + 3 H(2)O. (2) A long-chain acyl-CoA + 4 methylmalonyl-CoA + 8 NADPH + a holo- [mycocerosate synthase] synthase = a tetramethylated-mycocerosoyl- [mycocerosate synthase] + 5 CoA + 4 CO(2) + 8 NADP(+) + 4 H(2)O.
  • This mycobacterial enzyme loads long-chain fatty acyl groups from their CoA esters and extends them 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 products remain bound to the enzyme and require 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 A0A0N1NPH4 A0A0N1NPH4 G0PRM4 G0PRM4
[Acyl-carrier-protein] S-malonyltransferase. [EC: 2.3.1.39]
Malonyl-CoA + an [acyl-carrier-protein] = CoA + a malonyl-[acyl-carrier- protein].
  • Essential, along with EC 2.3.1.38, for the initiation of fatty-acid biosynthesis in bacteria.
  • Also provides the malonyl groups for polyketide biosynthesis.
  • The product of the reaction, malonyl-ACP, is an elongation substrate in fatty-acid biosynthesis.
  • In Mycobacterium tuberculosis, holo-ACP (the product of EC 2.7.8.7) is the preferred substrate.
  • This enzyme also forms part of the multienzyme complexes EC 4.1.1.88 and EC 4.1.1.89.
  • Malonylation of ACP is immediately followed by decarboxylation within the malonate-decarboxylase complex to yield acetyl-ACP, the catalytically active species of the decarboxylase.
  • In the enzyme from Klebsiella pneumoniae, methylmalonyl-CoA can also act as a substrate but acetyl-CoA cannot whereas the enzyme from Pseudomonas putida can use both as substrates.
  • The ACP subunit found in fatty-acid biosynthesis contains a pantetheine-4'-phosphate prosthetic group; that from malonate decarboxylase also contains pantetheine-4'-phosphate but in the form of a 2'-(5-triphosphoribosyl)-3'-dephospho-CoA prosthetic group.
 4 A0A0N1NXA8 A0A0N1NXA8 M9U189 M9U189
3-oxoacyl-[acyl-carrier-protein] reductase. [EC: 1.1.1.100]
(3R)-3-hydroxyacyl-[acyl-carrier-protein] + NADP(+) = 3-oxoacyl-[acyl- carrier-protein] + NADPH.
  • Exhibits a marked preference for [acyl-carrier-protein] derivatives over CoA derivatives as substrates.
 2 A0A0N0N6Y5 A0A0N0N6Y5
[Acyl-carrier-protein] S-acetyltransferase. [EC: 2.3.1.38]
Acetyl-CoA + [acyl-carrier-protein] = CoA + acetyl-[acyl-carrier- protein].
  • Essential, along with EC 2.3.1.39, for the initiation of fatty-acid biosynthesis in bacteria.
  • The substrate acetyl-CoA protects the enzyme against inhibition by N-ethylmaleimide or iodoacetamide.
  • This is one of the activities associated with EC 2.3.1.180.
 2 A0A0N0N6L5 A0A0N0N6L5
6-methylsalicylic acid synthase. [EC: 2.3.1.165]
Acetyl-CoA + 3 malonyl-CoA + NADPH = 6-methylsalicylate + 4 CoA + 3 CO(2) + NADP(+).
  • A multienzyme complex with a 4'-phosphopantetheine prosthetic group on the acyl carrier protein.
  • It has a similar sequence to vertebrate type I fatty acid synthase.
  • Acetoacetyl-CoA can also act as a starter molecule.
 2 G0PRM3 G0PRM3
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