1ude
Crystal structure of the Inorganic pyrophosphatase from the hyperthermophilic archaeon Pyrococcus horikoshii OT3
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OverviewOverview
A homolog to the eubacteria inorganic pyrophosphatase (PPase, EC 3.6.1.1), was found in the genome of the hyperthermophilic archaeon Pyrococcus, horikoshii. This inorganic pyrophosphatase (Pho-PPase) grows optimally at, 88 degrees C. To understand the structural basis for the thermostability, of Pho-PPase, we have determined the crystal structure to 2.66 A, resolution. The crystallographic asymmetric unit contains three monomers, related by approximate threefold symmetry, and a hexamer is built up by, twofold crystallographic symmetry. The main-chain fold of Pho-PPase is, almost identical to that of the known crystal structure of the model from, Sulfolobus acidocaldarius. A detailed comparison of the crystal structure, of Pho-PPase with related structures from S. acidocaldarius, Thermus, thermophilus, and Escherichia coli shows significant differences that may, account for the difference in their thermostabilities. A reduction in, thermolabile residues, additional aromatic residues, and more intimate, association between subunits all contribute to the larger thermophilicity, of Pho-PPase. In particular, deletions in two loops surrounding the active, site help to stabilize its conformation, while ion-pair networks unique to, Pho-PPase are located in the active site and near the C-terminus. The, identification of structural features that make PPases more adaptable to, extreme temperature should prove helpful for future biotechnology, applications.
About this StructureAbout this Structure
1UDE is a Single protein structure of sequence from Pyrococcus horikoshii. Active as Inorganic diphosphatase, with EC number 3.6.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the hyperthermophilic inorganic pyrophosphatase from the archaeon Pyrococcus horikoshii., Liu B, Bartlam M, Gao R, Zhou W, Pang H, Liu Y, Feng Y, Rao Z, Biophys J. 2004 Jan;86(1 Pt 1):420-7. PMID:14695284
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