1qez
From Proteopedia
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| - | | | + | {{STRUCTURE_1qez| PDB=1qez | SCENE= }} |
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'''SULFOLOBUS ACIDOCALDARIUS INORGANIC PYROPHOSPHATASE: AN ARCHAEL PYROPHOSPHATASE.''' | '''SULFOLOBUS ACIDOCALDARIUS INORGANIC PYROPHOSPHATASE: AN ARCHAEL PYROPHOSPHATASE.''' | ||
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[[Category: Nummelin, H.]] | [[Category: Nummelin, H.]] | ||
[[Category: Schafer, G.]] | [[Category: Schafer, G.]] | ||
| - | [[Category: | + | [[Category: Inorganic pyrophosphatase]] |
| - | [[Category: | + | [[Category: Magnesium]] |
| - | [[Category: | + | [[Category: Thermostability]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:11:06 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 03:11, 3 May 2008
SULFOLOBUS ACIDOCALDARIUS INORGANIC PYROPHOSPHATASE: AN ARCHAEL PYROPHOSPHATASE.
Overview
The first crystal structure of an inorganic pyrophosphatase (S-PPase) from an archaebacterium, the thermophile Sulfolobus acidocaldarius, has been solved by molecular replacement and refined to an R-factor of 19.7% at 2.7 A. S-PPase is a D3 homohexameric protein with one Mg2+ per active site in a position similar to, but not identical with, the first activating metal in mesophilic pyrophosphatases (PPase). In mesophilic PPases, Asp65, Asp70, and Asp102 coordinate the Mg2+, while only Asp65 and Asp102 do in S-PPase, and the Mg2+ moves by 0.7 A. S-PPase may therefore be deactivated at low temperature by mispositioning a key metal ion. The monomer S-PPase structure is very similar to that of Thermus thermophilus (T-PPase) and Escherichia coli (E-PPase), root-mean-square deviations around 1 A/Calpha. But the hexamer structures of S- and T-PPase are more tightly packed and more similar to each other than they are to that of E-PPase, as shown by the increase in surface area buried upon oligomerization. In T-PPase, Arg116 creates an interlocking ionic network to both twofold and threefold related monomers; S-PPase has hydrophilic interactions to threefold related monomers absent in both E- and T-PPase. In addition, the thermostable PPases have about 7% more hydrogen bonds per monomer than E-PPase, and, especially in S-PPase, additional ionic interactions anchor the C-terminus to the rest of the protein. Thermostability in PPases is thus due to subtle improvements in both monomer and oligomer interactions.
About this Structure
1QEZ is a Single protein structure of sequence from Sulfolobus acidocaldarius. Full crystallographic information is available from OCA.
Reference
Sulfolobus acidocaldarius inorganic pyrophosphatase: structure, thermostability, and effect of metal ion in an archael pyrophosphatase., Leppanen VM, Nummelin H, Hansen T, Lahti R, Schafer G, Goldman A, Protein Sci. 1999 Jun;8(6):1218-31. PMID:10386872 Page seeded by OCA on Sat May 3 06:11:06 2008
