1gn8: Difference between revisions
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==Overview== | ==Overview== | ||
Phosphopantetheine adenylyltransferase (PPAT) is an essential enzyme in, the coenzyme A pathway that catalyzes the reversible transfer of an, adenylyl group from ATP to 4'-phosphopantetheine (Ppant) in the presence, of magnesium. To investigate the reaction mechanism, the high-resolution, crystal structures of the Escherichia coli PPAT have been determined in, the presence of either ATP or Ppant. Structural details of the catalytic, center revealed specific roles for individual amino acid residues involved, in substrate binding and catalysis. The side-chain of His18 stabilizes the, expected pentacovalent intermediate, whereas the side-chains of Thr10 and, Lys42 orient the nucleophile for an in-line displacement mechanism. The, binding site for the manganese ion that interacts with the .. | Phosphopantetheine adenylyltransferase (PPAT) is an essential enzyme in, the coenzyme A pathway that catalyzes the reversible transfer of an, adenylyl group from ATP to 4'-phosphopantetheine (Ppant) in the presence, of magnesium. To investigate the reaction mechanism, the high-resolution, crystal structures of the Escherichia coli PPAT have been determined in, the presence of either ATP or Ppant. Structural details of the catalytic, center revealed specific roles for individual amino acid residues involved, in substrate binding and catalysis. The side-chain of His18 stabilizes the, expected pentacovalent intermediate, whereas the side-chains of Thr10 and, Lys42 orient the nucleophile for an in-line displacement mechanism. The, binding site for the manganese ion that interacts with the phosphate, groups of the nucleotide has also been identified. Within the PPAT, hexamer, one trimer is in its substrate-free state, whereas the other is, in a substrate-bound state. | ||
==About this Structure== | ==About this Structure== | ||
1GN8 is a | 1GN8 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, MN and ATP 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] Structure known Active Site: ATA. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GN8 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 14:40:54 2007'' | ||
