1jt9
From Proteopedia
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| - | [[Image:1jt9.jpg|left|200px]] | + | [[Image:1jt9.jpg|left|200px]] |
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| - | '''Structure of the mutant F174A T form of the Glucosamine-6-Phosphate deaminase from E.coli''' | + | {{Structure |
| + | |PDB= 1jt9 |SIZE=350|CAPTION= <scene name='initialview01'>1jt9</scene>, resolution 2.06Å | ||
| + | |SITE= | ||
| + | |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] | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''Structure of the mutant F174A T form of the Glucosamine-6-Phosphate deaminase from E.coli''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1JT9 is a [ | + | 1JT9 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JT9 OCA]. |
==Reference== | ==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:[http:// | + | 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:[http://www.ncbi.nlm.nih.gov/pubmed/12051945 12051945] |
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Glucosamine-6-phosphate deaminase]] | [[Category: Glucosamine-6-phosphate deaminase]] | ||
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[[Category: aldose-ketose isomerase]] | [[Category: aldose-ketose isomerase]] | ||
[[Category: allosteric enzyme]] | [[Category: allosteric enzyme]] | ||
| - | [[Category: entropic | + | [[Category: entropic effect]] |
[[Category: structural flexibility]] | [[Category: structural flexibility]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 12:08:14 2008'' |
Revision as of 10:08, 20 March 2008
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| , resolution 2.06Å | |||||||
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| Activity: | Glucosamine-6-phosphate deaminase, with EC number 3.5.99.6 | ||||||
| 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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