1u7o
From Proteopedia
(New page: 200px<br /><applet load="1u7o" size="450" color="white" frame="true" align="right" spinBox="true" caption="1u7o, resolution 1.90Å" /> '''Magnesium Dependent ...) |
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| - | [[Image:1u7o.jpg|left|200px]]<br /><applet load="1u7o" size=" | + | [[Image:1u7o.jpg|left|200px]]<br /><applet load="1u7o" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1u7o, resolution 1.90Å" /> | caption="1u7o, resolution 1.90Å" /> | ||
'''Magnesium Dependent Phosphatase 1 (MDP-1)'''<br /> | '''Magnesium Dependent Phosphatase 1 (MDP-1)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The haloacid dehalogenase (HAD) superfamily is comprised of structurally | + | The haloacid dehalogenase (HAD) superfamily is comprised of structurally homologous enzymes that share several conserved sequence motifs (loops I-IV) in their active site. The majority of HAD members are phosphohydrolases and may be divided into three subclasses depending on domain organization. In classes I and II, a mobile "cap" domain reorients upon substrate binding, closing the active site to bulk solvent. Members of the third class lack this additional domain. Herein, we report the 1.9 A X-ray crystal structures of a member of the third subclass, magnesium-dependent phosphatase-1 (MDP-1) both in its unliganded form and with the product analogue, tungstate, bound to the active site. The secondary structure of MDP-1 is similar to that of the "core" domain of other type I and type II HAD members with the addition of a small, 28-amino acid insert that does not close down to exclude bulk solvent in the presence of ligand. In addition, the monomeric oligomeric state of MDP-1 does not allow the participation of a second subunit in the formation and solvent protection of the active site. The binding sites for the phosphate portion of the substrate and Mg(II) cofactor are also similar to those of other HAD members, with all previously observed contacts conserved. Unlike other subclass III HAD members, MDP-1 appears to be equally able to dephosphorylate phosphotyrosine and closed-ring phosphosugars. Modeling of possible substrates in the active site of MDP-1 reveals very few potential interactions with the substrate leaving group. The mapping of conserved residues in sequences of MDP-1 from different eukaryotic organisms reveals that they colocalize to a large region on the surface of the protein outside the active site. This observation combined with the modeling studies suggests that the target of MDP-1 is most likely a phosphotyrosine in an unknown protein rather than a small sugar-based substrate. |
==About this Structure== | ==About this Structure== | ||
| - | 1U7O is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus] with ACT as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1U7O is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus] with <scene name='pdbligand=ACT:'>ACT</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1U7O OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Mus musculus]] | [[Category: Mus musculus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Allen, K | + | [[Category: Allen, K N.]] |
[[Category: Dunaway-Mariano, D.]] | [[Category: Dunaway-Mariano, D.]] | ||
[[Category: Peisach, E.]] | [[Category: Peisach, E.]] | ||
| - | [[Category: Selengut, J | + | [[Category: Selengut, J D.]] |
[[Category: ACT]] | [[Category: ACT]] | ||
[[Category: aspartate nucleophile]] | [[Category: aspartate nucleophile]] | ||
| Line 26: | Line 26: | ||
[[Category: structural enzymology]] | [[Category: structural enzymology]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:21:25 2008'' |
Revision as of 13:21, 21 February 2008
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Magnesium Dependent Phosphatase 1 (MDP-1)
Overview
The haloacid dehalogenase (HAD) superfamily is comprised of structurally homologous enzymes that share several conserved sequence motifs (loops I-IV) in their active site. The majority of HAD members are phosphohydrolases and may be divided into three subclasses depending on domain organization. In classes I and II, a mobile "cap" domain reorients upon substrate binding, closing the active site to bulk solvent. Members of the third class lack this additional domain. Herein, we report the 1.9 A X-ray crystal structures of a member of the third subclass, magnesium-dependent phosphatase-1 (MDP-1) both in its unliganded form and with the product analogue, tungstate, bound to the active site. The secondary structure of MDP-1 is similar to that of the "core" domain of other type I and type II HAD members with the addition of a small, 28-amino acid insert that does not close down to exclude bulk solvent in the presence of ligand. In addition, the monomeric oligomeric state of MDP-1 does not allow the participation of a second subunit in the formation and solvent protection of the active site. The binding sites for the phosphate portion of the substrate and Mg(II) cofactor are also similar to those of other HAD members, with all previously observed contacts conserved. Unlike other subclass III HAD members, MDP-1 appears to be equally able to dephosphorylate phosphotyrosine and closed-ring phosphosugars. Modeling of possible substrates in the active site of MDP-1 reveals very few potential interactions with the substrate leaving group. The mapping of conserved residues in sequences of MDP-1 from different eukaryotic organisms reveals that they colocalize to a large region on the surface of the protein outside the active site. This observation combined with the modeling studies suggests that the target of MDP-1 is most likely a phosphotyrosine in an unknown protein rather than a small sugar-based substrate.
About this Structure
1U7O is a Single protein structure of sequence from Mus musculus with as ligand. Full crystallographic information is available from OCA.
Reference
X-ray crystal structure of the hypothetical phosphotyrosine phosphatase MDP-1 of the haloacid dehalogenase superfamily., Peisach E, Selengut JD, Dunaway-Mariano D, Allen KN, Biochemistry. 2004 Oct 12;43(40):12770-9. PMID:15461449
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