1jt9
From Proteopedia
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|SITE= | |SITE= | ||
|LIGAND= | |LIGAND= | ||
| - | |ACTIVITY= [http://en.wikipedia.org/wiki/Glucosamine-6-phosphate_deaminase Glucosamine-6-phosphate deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.99.6 3.5.99.6] | + | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Glucosamine-6-phosphate_deaminase Glucosamine-6-phosphate deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.99.6 3.5.99.6] </span> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1cd5|1cd5]], [[1fs6|1fs6]], [[1fsf|1fsf]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1jt9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jt9 OCA], [http://www.ebi.ac.uk/pdbsum/1jt9 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1jt9 RCSB]</span> | ||
}} | }} | ||
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[[Category: structural flexibility]] | [[Category: structural flexibility]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:38:41 2008'' |
Revision as of 18:38, 30 March 2008
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| , resolution 2.06Å | |||||||
|---|---|---|---|---|---|---|---|
| Activity: | Glucosamine-6-phosphate deaminase, with EC number 3.5.99.6 | ||||||
| Related: | 1cd5, 1fs6, 1fsf
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structure of the mutant F174A T form of the Glucosamine-6-Phosphate deaminase from E.coli
Overview
The active site of glucosamine-6-phosphate deaminase from Escherichia coli (GlcN6P deaminase, EC 3.5.99.6) has a complex lid formed by two antiparallel beta-strands connected by a helix-loop segment (158-187). This motif contains Arg172, which is a residue involved in binding the substrate in the active-site, and three residues that are part of the allosteric site, Arg158, Lys160 and Thr161. This dual binding role of the motif forming the lid suggests that it plays a key role in the functional coupling between active and allosteric sites. Previous crystallographic work showed that the temperature coefficients of the active-site lid are very large when the enzyme is in its T allosteric state. These coefficients decrease in the R state, thus suggesting that this motif changes its conformational flexibility as a consequence of the allosteric transition. In order to explore the possible connection between the conformational flexibility of the lid and the function of the deaminase, we constructed the site-directed mutant Phe174-Ala. Phe174 is located at the C-end of the lid helix and its side-chain establishes hydrophobic interactions with the remainder of the enzyme. The crystallographic structure of the T state of Phe174-Ala deaminase, determined at 2.02 A resolution, shows no density for the segment 162-181, which is part of the active-site lid (PDB 1JT9). This mutant form of the enzyme is essentially inactive in the absence of the allosteric activator, N-acetylglucosamine-6-P although it recovers its activity up to the wild-type level in the presence of this ligand. Spectrometric and binding studies show that inactivity is due to the inability of the active-site to bind ligands when the allosteric site is empty. These data indicate that the conformational flexibility of the active-site lid critically alters the binding properties of the active site, and that the occupation of the allosteric site restores the lid conformational flexibility to a functional state.
About this Structure
1JT9 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
On the role of the conformational flexibility of the active-site lid on the allosteric kinetics of glucosamine-6-phosphate deaminase., Bustos-Jaimes I, Sosa-Peinado A, Rudino-Pinera E, Horjales E, Calcagno ML, J Mol Biol. 2002 May 24;319(1):183-9. PMID:12051945
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