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CATH Superfamily 3.40.50.150

Vaccinia Virus protein VP39

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 named:

"
Vaccinia Virus protein VP39
".

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 134333: Polyketide synthase, rhizoxin biosynthesis

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.
 6 A0A0E1LPY5 C7PSF7 C7PSF7 F1TAA5 F1TIW0 I2C5F1
[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.
 5 A0A0C5V8K3 A0A0C5VN28 A0A0C5VQN4 A0A0K0PDE8 A0A0K0PEE9
Beta-ketoacyl-[acyl-carrier-protein] synthase II. [EC: 2.3.1.179]
(Z)-hexadec-11-enoyl-[acyl-carrier-protein] + malonyl-[acyl-carrier- protein] = (Z)-3-oxooctadec-13-enoyl-[acyl-carrier-protein] + CO(2) + [acyl-carrier-protein].
  • Involved in the dissociated (or type II) fatty acid biosynthesis system that occurs in plants and bacteria.
  • While the substrate specificity of this enzyme is very similar to that of EC 2.3.1.41, it differs in that palmitoleoyl-ACP is not a good substrate of EC 2.3.1.41 but is an excellent substrate of this enzyme.
  • The fatty-acid composition of Escherichia coli changes as a function of growth temperature, with the proportion of unsaturated fatty acids increasing with lower growth temperature.
  • Controls the temperature-dependent regulation of fatty-acid composition, with mutants lacking this acivity being deficient in the elongation of palmitoleate to cis-vaccenate at low temperatures.
 3 A0A095G6H9 A0A1G4LJG3 S6G265
Long-chain-fatty-acid--CoA ligase. [EC: 6.2.1.3]
ATP + a long-chain fatty acid + CoA = AMP + diphosphate + an acyl-CoA.
  • Acts on a wide range of long-chain saturated and unsaturated fatty acids, but the enzymes from different tissues show some variation in specificity.
  • The liver enzyme acts on acids from C(6) to C(20); that from brain shows high activity up to C(24).
 2 A0A0E1LPY5 I2C5F1
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 C7PSF7 C7PSF7
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.
 1 A0A150KYQ2
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.
 1 F1TIW0
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