1i74
From Proteopedia
(New page: 200px<br /><applet load="1i74" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i74, resolution 2.2Å" /> '''STREPTOCOCCUS MUTANS ...) |
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| - | [[Image:1i74.gif|left|200px]]<br /><applet load="1i74" size=" | + | [[Image:1i74.gif|left|200px]]<br /><applet load="1i74" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1i74, resolution 2.2Å" /> | caption="1i74, resolution 2.2Å" /> | ||
'''STREPTOCOCCUS MUTANS INORGANIC PYROPHOSPHATASE'''<br /> | '''STREPTOCOCCUS MUTANS INORGANIC PYROPHOSPHATASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Streptococcus mutans pyrophosphatase (Sm-PPase) is a member of | + | BACKGROUND: Streptococcus mutans pyrophosphatase (Sm-PPase) is a member of a relatively uncommon but widely dispersed sequence family (family II) of inorganic pyrophosphatases. A structure will answer two main questions: is it structurally similar to the family I PPases, and is the mechanism similar? RESULTS: The first family II PPase structure, that of homodimeric Sm-PPase complexed with metal and sulfate ions, has been solved by X-ray crystallography at 2.2 A resolution. The tertiary fold of Sm-PPase consists of a 189 residue alpha/beta N-terminal domain and a 114 residue mixed beta sheet C-terminal domain and bears no resemblance to family I PPase, even though the arrangement of active site ligands and the residues that bind them shows significant similarity. The preference for Mn2+ over Mg2+ in family II PPases is explained by the histidine ligands and bidentate carboxylate coordination. The active site is located at the domain interface. The C-terminal domain is hinged to the N-terminal domain and exists in both closed and open conformations. CONCLUSIONS: The active site similiarities, including a water coordinated to two metal ions, suggest that the family II PPase mechanism is "analogous" (not "homologous") to that of family I PPases. This is a remarkable example of convergent evolution. The large change in C-terminal conformation suggests that domain closure might be the mechanism by which Sm-PPase achieves specificity for pyrophosphate over other polyphosphates. |
==About this Structure== | ==About this Structure== | ||
| - | 1I74 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_mutans Streptococcus mutans] with MN, MG and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Inorganic_diphosphatase Inorganic diphosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.6.1.1 3.6.1.1] Full crystallographic information is available from [http:// | + | 1I74 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_mutans Streptococcus mutans] with <scene name='pdbligand=MN:'>MN</scene>, <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Inorganic_diphosphatase Inorganic diphosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.6.1.1 3.6.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1I74 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptococcus mutans]] | [[Category: Streptococcus mutans]] | ||
| - | [[Category: Fabrichniy, I | + | [[Category: Fabrichniy, I P.]] |
[[Category: Goldman, A.]] | [[Category: Goldman, A.]] | ||
[[Category: Lahti, R.]] | [[Category: Lahti, R.]] | ||
| - | [[Category: Merckel, M | + | [[Category: Merckel, M C.]] |
[[Category: Salminen, A.]] | [[Category: Salminen, A.]] | ||
[[Category: MG]] | [[Category: MG]] | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:08:38 2008'' |
Revision as of 11:08, 21 February 2008
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STREPTOCOCCUS MUTANS INORGANIC PYROPHOSPHATASE
Overview
BACKGROUND: Streptococcus mutans pyrophosphatase (Sm-PPase) is a member of a relatively uncommon but widely dispersed sequence family (family II) of inorganic pyrophosphatases. A structure will answer two main questions: is it structurally similar to the family I PPases, and is the mechanism similar? RESULTS: The first family II PPase structure, that of homodimeric Sm-PPase complexed with metal and sulfate ions, has been solved by X-ray crystallography at 2.2 A resolution. The tertiary fold of Sm-PPase consists of a 189 residue alpha/beta N-terminal domain and a 114 residue mixed beta sheet C-terminal domain and bears no resemblance to family I PPase, even though the arrangement of active site ligands and the residues that bind them shows significant similarity. The preference for Mn2+ over Mg2+ in family II PPases is explained by the histidine ligands and bidentate carboxylate coordination. The active site is located at the domain interface. The C-terminal domain is hinged to the N-terminal domain and exists in both closed and open conformations. CONCLUSIONS: The active site similiarities, including a water coordinated to two metal ions, suggest that the family II PPase mechanism is "analogous" (not "homologous") to that of family I PPases. This is a remarkable example of convergent evolution. The large change in C-terminal conformation suggests that domain closure might be the mechanism by which Sm-PPase achieves specificity for pyrophosphate over other polyphosphates.
About this Structure
1I74 is a Single protein structure of sequence from Streptococcus mutans with , and as ligands. Active as Inorganic diphosphatase, with EC number 3.6.1.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of Streptococcus mutans pyrophosphatase: a new fold for an old mechanism., Merckel MC, Fabrichniy IP, Salminen A, Kalkkinen N, Baykov AA, Lahti R, Goldman A, Structure. 2001 Apr 4;9(4):289-97. PMID:11525166
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