2prd
From Proteopedia
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CRYSTAL STRUCTURE OF INORGANIC PYROPHOSPHATASE FROM THERMUS THERMOPHILUS
Overview
The 3-dimensional structure of inorganic pyrophosphatase from Thermus, thermophilus (T-PPase) has been determined by X-ray diffraction at 2.0 A, resolution and refined to R = 15.3%. The structure consists of an, antiparallel closed beta-sheet and 2 alpha-helices and resembles that of, the yeast enzyme in spite of the large difference in size (174 and 286, residues, respectively), little sequence similarity beyond the active, center (about 20%), and different oligomeric organization (hexameric and, dimeric, respectively). The similarity of the polypeptide folding in the 2, PPases provides a very strong argument in favor of an evolutionary, relationship between the yeast and bacterial enzymes. The same Greek-key, topology of the 5-stranded beta-barrel was found in the OB-fold proteins, the bacteriophage gene-5 DNA-binding protein, toxic-shock syndrome, toxin-1, and the major cold-shock protein of Bacillus subtilis. Moreover, all known nucleotide-binding sites in these proteins are located on the, same side of the beta-barrel as the active center in T-PPase. Analysis of, the active center of T-PPase revealed 17 residues of potential functional, importance, 16 of which are strictly conserved in all sequences of soluble, PPases. Their possible role in the catalytic mechanism is discussed on the, basis of the present crystal structure and with respect to site-directed, mutagenesis studies on the Escherichia coli enzyme. The observed, oligomeric organization of T-PPase allows us to suggest a possible, mechanism for the allosteric regulation of hexameric PPases.
About this Structure
2PRD is a Single protein structure of sequence from Thermus thermophilus with SO4 as ligand. Active as Inorganic diphosphatase, with EC number 3.6.1.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of inorganic pyrophosphatase from Thermus thermophilus., Teplyakov A, Obmolova G, Wilson KS, Ishii K, Kaji H, Samejima T, Kuranova I, Protein Sci. 1994 Jul;3(7):1098-107. PMID:7920256
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