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| CATH domain | Related DB codes (homologues) |
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| 3.40.50.620 | S00314,S00549,S00316,S00318,S00315,T00085,T00249,D00300,M00177,M00178,T00106,T00114 |
| Enzyme Name | | Swiss-prot | KEGG |
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| P0A6I6 |
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| Protein name | Phosphopantetheine adenylyltransferase | pantetheine-phosphate adenylyltransferasedephospho-CoA pyrophosphorylasepantetheine phosphate adenylyltransferasedephospho-coenzyme A pyrophosphorylase3'-dephospho-CoA pyrophosphorylase |
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| Synonyms | EC 2.7.7.3Pantetheine-phosphate adenylyltransferasePPATDephospho-CoA pyrophosphorylase |
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| KEGG pathways | | MAP code | Pathways |
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| MAP00770 | Pantothenate and CoA biosynthesis |
| Swiss-prot:Accession Number | P0A6I6 |
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| Entry name | COAD_ECOLI |
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| Activity | ATP + pantetheine 4''-phosphate = diphosphate + 3''-dephospho-CoA. |
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| Subunit | Homohexamer. |
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| Subcellular location | Cytoplasm. |
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| Cofactor |
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| Cofactors | Substrates | Products |
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| KEGG-id | C00305 | C00002 | C01134 | C00013 | C00882 |
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| Compound | Magnesium | ATP | Pantetheine 4'-phosphate | Pyrophosphate | Dephospho-CoA |
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| Type | divalent metal (Ca2+, Mg2+) | amine group,nucleotide | carbohydrate,peptide/protein,phosphate group/phosphate ion,sulfhydryl group | phosphate group/phosphate ion | amine group,carbohydrate,nucleotide,peptide/protein,sulfhydryl group |
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| 1b6tA |  | Unbound | Unbound | Unbound | Unbound | Unbound |
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| 1b6tB | | Unbound | Unbound | Unbound | Unbound | Bound:COD |
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| 1qjcA | | Unbound | Unbound | Unbound | Unbound | Unbound |
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| 1qjcB | | Unbound | Unbound | Bound:PNS | Unbound | Unbound |
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| 1gn8A | | Analogue:_MN | Bound:ATP | Unbound | Unbound | Unbound |
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| 1gn8B | | Analogue:_MN | Bound:ATP | Unbound | Unbound | Unbound |
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| 1h1tA | | Unbound | Unbound | Unbound | Unbound | Analogue:COA |
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| 1h1tB | | Unbound | Unbound | Bound:PNS | Unbound | Unbound |
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| References for Catalytic Mechanism | | References | Sections | No. of steps in catalysis |
|---|
| [1] | p.2025-2027 |
| | [2] | p.27111 |
| | [4] | Fig.3, p.493-494 |
|
| references | | [1] |
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| PubMed ID | 10205156 |
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| Journal | EMBO J |
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| Year | 1999 |
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| Volume | 18 |
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| Pages | 2021-30 |
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| Authors | Izard T, Geerlof A |
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| Title | The crystal structure of a novel bacterial adenylyltransferase reveals half of sites reactivity. |
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| Related PDB | 1b6t |
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| Related Swiss-prot | P0A6I6 |
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| [2] |
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| PubMed ID | 10480925 |
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| Journal | J Biol Chem |
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| Year | 1999 |
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| Volume | 274 |
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| Pages | 27105-11 |
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| Authors | Geerlof A, Lewendon A, Shaw WV |
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| Title | Purification and characterization of phosphopantetheine adenylyltransferase from Escherichia coli. |
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| [3] |
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| PubMed ID | 10329792 |
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| Journal | Acta Crystallogr D Biol Crystallogr |
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| Year | 1999 |
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| Volume | 55 |
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| Pages | 1226-8 |
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| Authors | Izard T, Geerlof A, Lewendon A, Barker JJ |
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| Title | Cubic crystals of phosphopantetheine adenylyltransferase from Escherichia coli. |
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| [4] |
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| PubMed ID | 11812124 |
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| Journal | J Mol Biol |
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| Year | 2002 |
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| Volume | 315 |
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| Pages | 487-95 |
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| Authors | Izard T |
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| Title | The crystal structures of phosphopantetheine adenylyltransferase with bound substrates reveal the enzyme's catalytic mechanism. |
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| Related PDB | 1qjc,1gn8 |
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| [5] |
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| PubMed ID | 12837781 |
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| Journal | J Bacteriol |
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| Year | 2003 |
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| Volume | 185 |
|---|
| Pages | 4074-80 |
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| Authors | Izard T |
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| Title | A novel adenylate binding site confers phosphopantetheine adenylyltransferase interactions with coenzyme A. |
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| Related PDB | 1h1t |
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| comments | This enzyme catalyzes the transfer of an adenylyl group, whose reactive site is alpha-phosphate group, from ATP to 4'-phosphopantetheine (PPANT) in the presence of magnesium, according to the literature [4]. Here, the adenylyl group and pyrophosphate composed of beta- and gamma- phosphate of ATP are the transferred group and leaving group (donor group), respectively, whilst the 4'-phosphate of PPANT is acceptor group, in this transfer reaction.
According to the paper [4], the 4'-phosphate of PPANT makes a nucleophilic attack on the alpha-phosphate of nucleotide in an in-line displacement mechanism. During this reaction, this enzyme lowers the activation energy barrier by orienting the nucleotide and stabilizing the pentacovalent transition state.
His18 plays an essential role, by interacting with alpha-phosphate group of ATP, during the transition state stabilization. In addition, Lys42 and Thr10 orient the nucleophile, 4'-phosphate group of PPANT, whilst the sidechain of Arg91, Ser128 and Ser130 and the amide group of Ser129 stabilize the beta and gamma-phosphate group of ATP.
In the crystal structure of this enzyme, the catalytic metal ion is coordinated by the non-esterified oxygen atoms of all three phosphate groups of ATP, whilst the enzyme sidechians contributing to the coordination of the cation could not be found [4]. This result suggests that the catalytic ion might contribute to both the transferred group and leaving group (donor group) of ATP.
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| created | updated |
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| 2002-05-29 | 2009-02-26 |
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