2j4h
From Proteopedia
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| - | [[Image:2j4h.jpg|left|200px]]<br /><applet load="2j4h" size=" | + | [[Image:2j4h.jpg|left|200px]]<br /><applet load="2j4h" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2j4h, resolution 2.70Å" /> | caption="2j4h, resolution 2.70Å" /> | ||
'''CRYSTAL STRUCTURE OF A H121A ESCHERICHIA COLI DCTP DEAMINASE MUTANT ENZYME'''<br /> | '''CRYSTAL STRUCTURE OF A H121A ESCHERICHIA COLI DCTP DEAMINASE MUTANT ENZYME'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 2J4H 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 MG and YYY as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/dCTP_deaminase dCTP deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.4.13 3.5.4.13] Known structural/functional Site: <scene name='pdbsite=AC1:Mg Binding Site For Chain B'>AC1</scene>. Full crystallographic information is available from [http:// | + | 2J4H 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=MG:'>MG</scene> and <scene name='pdbligand=YYY:'>YYY</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/dCTP_deaminase dCTP deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.4.13 3.5.4.13] Known structural/functional Site: <scene name='pdbsite=AC1:Mg Binding Site For Chain B'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2J4H OCA]. |
==Reference== | ==Reference== | ||
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[[Category: trimer]] | [[Category: trimer]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 13:56:14 2008'' |
Revision as of 11:56, 23 January 2008
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CRYSTAL STRUCTURE OF A H121A ESCHERICHIA COLI DCTP DEAMINASE MUTANT ENZYME
Overview
The trimeric dCTP deaminase produces dUTP that is hydrolysed to dUMP by, the structurally closely related dUTPase. This pathway provides 70-80% of, the total dUMP as a precursor for dTTP. Accordingly, dCTP deaminase is, regulated by dTTP, which increases the substrate concentration for, half-maximal activity and the cooperativity of dCTP saturation. Likewise, increasing concentrations of dCTP increase the cooperativity of dTTP, inhibition. Previous structural studies showed that the complexes of, inactive mutant protein, E138A, with dUTP or dCTP bound, and wild-type, enzyme with dUTP bound were all highly similar and characterized by having, an ordered C-terminal. When comparing with a new structure in which dTTP, is bound to the active site of E138A, the region between Val120 and His125, was found to be in a new conformation. This and the previous conformation, were mutually exclusive within the trimer. Also, the dCTP complex of the, inactive H121A was found to have residues 120-125 in this new, conformation, indicating that it renders the enzyme inactive. The, C-terminal fold was found to be disordered for both new complexes. We, suggest that the cooperative kinetics are imposed by a dTTP-dependent lag, of product formation observed in presteady-state kinetics. This lag may be, derived from a slow equilibration between an inactive and an active, conformation of dCTP deaminase represented by the dTTP complex and the, dUTP/dCTP complex, respectively. The dCTP deaminase then resembles a, simple concerted system subjected to effector binding, but without the use, of an allosteric site.
About this Structure
2J4H is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as dCTP deaminase, with EC number 3.5.4.13 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Regulation of dCTP deaminase from Escherichia coli by nonallosteric dTTP binding to an inactive form of the enzyme., Johansson E, Thymark M, Bynck JH, Fano M, Larsen S, Willemoes M, FEBS J. 2007 Aug;274(16):4188-98. Epub 2007 Jul 25. PMID:17651436
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Categories: Escherichia coli | Single protein | DCTP deaminase | Bynck, J.H. | Fanoe, M. | Johansson, E. | Larsen, S. | Thymark, M. | Willemoes, M. | MG | YYY | Dctp deaminase | Hydrolase | Nucleotide metabolism | Trimer
