1b6t
From Proteopedia
(New page: 200px<br /><applet load="1b6t" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b6t, resolution 1.80Å" /> '''PHOSPHOPANTETHEINE A...) |
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| - | [[Image:1b6t.gif|left|200px]]<br /><applet load="1b6t" size=" | + | [[Image:1b6t.gif|left|200px]]<br /><applet load="1b6t" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1b6t, resolution 1.80Å" /> | caption="1b6t, resolution 1.80Å" /> | ||
'''PHOSPHOPANTETHEINE ADENYLYLTRANSFERASE IN COMPLEX WITH 3'-DEPHOSPHO-COA FROM ESCHERICHIA COLI'''<br /> | '''PHOSPHOPANTETHEINE ADENYLYLTRANSFERASE IN COMPLEX WITH 3'-DEPHOSPHO-COA FROM ESCHERICHIA COLI'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Phosphopantetheine adenylyltransferase (PPAT) is an essential enzyme in | + | Phosphopantetheine adenylyltransferase (PPAT) is an essential enzyme in bacteria that catalyses a rate-limiting step in coenzyme A (CoA) biosynthesis, by transferring an adenylyl group from ATP to 4'-phosphopantetheine, yielding dephospho-CoA (dPCoA). Each phosphopantetheine adenylyltransferase (PPAT) subunit displays a dinucleotide-binding fold that is structurally similar to that in class I aminoacyl-tRNA synthetases. Superposition of bound adenylyl moieties from dPCoA in PPAT and ATP in aminoacyl-tRNA synthetases suggests nucleophilic attack by the 4'-phosphopantetheine on the alpha-phosphate of ATP. The proposed catalytic mechanism implicates transition state stabilization by PPAT without involving functional groups of the enzyme in a chemical sense in the reaction. The crystal structure of the enzyme from Escherichia coli in complex with dPCoA shows that binding at one site causes a vice-like movement of active site residues lining the active site surface. The mode of enzyme product formation is highly concerted, with only one trimer of the PPAT hexamer showing evidence of dPCoA binding. The homologous active site attachment of ATP and the structural distribution of predicted sequence-binding motifs in PPAT classify the enzyme as belonging to the nucleotidyltransferase superfamily. |
==About this Structure== | ==About this Structure== | ||
| - | 1B6T is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 and COD as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Pantetheine-phosphate_adenylyltransferase Pantetheine-phosphate adenylyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.3 2.7.7.3] Full crystallographic information is available from [http:// | + | 1B6T is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=COD:'>COD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Pantetheine-phosphate_adenylyltransferase Pantetheine-phosphate adenylyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.3 2.7.7.3] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B6T OCA]. |
==Reference== | ==Reference== | ||
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[[Category: coenzyme a biosynthesis]] | [[Category: coenzyme a biosynthesis]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:52:13 2008'' |
Revision as of 09:52, 21 February 2008
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PHOSPHOPANTETHEINE ADENYLYLTRANSFERASE IN COMPLEX WITH 3'-DEPHOSPHO-COA FROM ESCHERICHIA COLI
Overview
Phosphopantetheine adenylyltransferase (PPAT) is an essential enzyme in bacteria that catalyses a rate-limiting step in coenzyme A (CoA) biosynthesis, by transferring an adenylyl group from ATP to 4'-phosphopantetheine, yielding dephospho-CoA (dPCoA). Each phosphopantetheine adenylyltransferase (PPAT) subunit displays a dinucleotide-binding fold that is structurally similar to that in class I aminoacyl-tRNA synthetases. Superposition of bound adenylyl moieties from dPCoA in PPAT and ATP in aminoacyl-tRNA synthetases suggests nucleophilic attack by the 4'-phosphopantetheine on the alpha-phosphate of ATP. The proposed catalytic mechanism implicates transition state stabilization by PPAT without involving functional groups of the enzyme in a chemical sense in the reaction. The crystal structure of the enzyme from Escherichia coli in complex with dPCoA shows that binding at one site causes a vice-like movement of active site residues lining the active site surface. The mode of enzyme product formation is highly concerted, with only one trimer of the PPAT hexamer showing evidence of dPCoA binding. The homologous active site attachment of ATP and the structural distribution of predicted sequence-binding motifs in PPAT classify the enzyme as belonging to the nucleotidyltransferase superfamily.
About this Structure
1B6T is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Pantetheine-phosphate adenylyltransferase, with EC number 2.7.7.3 Full crystallographic information is available from OCA.
Reference
The crystal structure of a novel bacterial adenylyltransferase reveals half of sites reactivity., Izard T, Geerlof A, EMBO J. 1999 Apr 15;18(8):2021-30. PMID:10205156
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