Sulfolobus acidocaldarius inorganic pyrophosphatase: structure, thermostability, and effect of metal ion in an archael pyrophosphatase.


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. Study holds ProTherm entries: 6730, 6731, 6732, 6733, 6734, 6735, 6736, 6737 Extra Details: additive : EDTA(5 mM),

Submission Details

ID: tQTdsAz94

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:32 p.m.

Version: 1

Publication Details
Leppänen VM;Nummelin H;Hansen T;Lahti R;Schäfer G;Goldman A,Protein Sci. (1999) Sulfolobus acidocaldarius inorganic pyrophosphatase: structure, thermostability, and effect of metal ion in an archael pyrophosphatase. PMID:10386872
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Inorganic pyrophosphatase P0A7B0 IPYR_ECO57
100.0 Inorganic pyrophosphatase P0A7A9 IPYR_ECOLI
98.9 Inorganic pyrophosphatase Q8FAG0 IPYR_ECOL6
94.3 Inorganic pyrophosphatase P65749 IPYR_SALTI
94.3 Inorganic pyrophosphatase P65748 IPYR_SALTY
91.4 Inorganic pyrophosphatase Q8ZB98 IPYR_YERPE
100.0 Inorganic pyrophosphatase P50308 IPYR_SULAC
100.0 Inorganic pyrophosphatase P38576 IPYR_THET8