Disease relevance of ppa

• Cloning and characterization of the gene encoding inorganic pyrophosphatase of Escherichia coli K-12 [1].
• To study the role of PPi in phloem cells, a chimeric gene was constructed using the phloem-specific rolC promoter of Agrobacterium rhizogenes to drive the expression of the ppa gene [2].
• Expression studies of two paralogous ppa genes encoding distinct Family I pyrophosphatases in marine unicellular cyanobacteria reveal inactivation of the typical cyanobacterial gene [3].
• Protein sequence alignment and phylogenetic analysis indicated that the ppa gene proper of cyanobacteria (ppa1) encodes a presumably inactive mutant enzyme whereas the second gene (ppa2) might encode an active sPPase closely related to those of some proteobacteria [3].
• We have cloned the inorganic pyrophosphatase gene (ppa) from the facultative intracellular pathogen Bartonella bacilliformis and characterized its encoded product [4].

High impact information on ppa

• Directed mutagenesis studies of the metal binding site at the subunit interface of Escherichia coli inorganic pyrophosphatase [5].
• The structures of Escherichia coli inorganic pyrophosphatase complexed with Ca(2+) or CaPP(i) at atomic resolution and their mechanistic implications [6].
• Transgenic plants were constructed expressing a novel cytosolic inorganic pyrophosphatase in order to reduce the cytosolic pyrophosphate content [7].
• To this end the Escherichia coli gene ppa encoding inorganic pyrophosphatase was cloned between the 35S CaMV promoter and the poly(A) site of the octopine synthase gene and transferred into tobacco and potato plants by Agrobacterium-mediated gene transfer [7].
• Effect of replacement of His-118, His-125 and Trp-143 by alanine on the catalytic activity and subunit assembly of inorganic pyrophosphatase from thermophilic bacterium PS-3 [8].

Chemical compound and disease context of ppa

• Structural and functional consequences of substitutions at the tyrosine 55-lysine 104 hydrogen bond in Escherichia coli inorganic pyrophosphatase [9].
• Crystalline holo inorganic pyrophosphatase from Escherichia coli was grown in the presence of 250 mM MgCl2 [10].
• Tyrosine 55 and lysine 104 are evolutionarily conserved residues that form a hydrogen bond in the active site of Escherichia coli inorganic pyrophosphatase (E-PPase) [9].
• Crystal structure of Escherichia coli inorganic pyrophosphatase complexed with SO4(2-). Ligand-induced molecular asymmetry [11].
• The three-dimensional structure of inorganic pyrophosphatase from Escherichia coli complexed with sulfate was determined at 2.2 A resolution using Patterson's search technique and refmed to an R-factor of 19.2% [11].

Biological context of ppa

• The structural gene of ppa contains 528 base pairs, from which a 175-amino-acid translation product, Mr 19,572, was deduced [1].
• Many different L. pneumophila loci are able to transform L. pneumophila after addition of plasmid DNA, including gspA, ppa, asd, and pilEL [12].
• Crystal structure of holo inorganic pyrophosphatase from Escherichia coli at 1.9 A resolution. Mechanism of hydrolysis [10].
• The refined crystal structures of hexameric soluble inorganic pyrophosphatase from E. coli (E-PPase) are reported to R factors of 18.7 and 18.3% at 2.15 and 2.2 A, respectively [13].
• A recombinant with a chromosomal ppa::Kanr lesion and a temperature-sensitive replicon with a ppa+ gene showed a temperature-sensitive growth phenotype, and a mutant with the sole ppa+ gene under control of the lac promoter showed inducer-dependent growth [14].

Anatomical context of ppa

• Overexpression of inorganic pyrophosphatase (PPase) from Escherichia coli in the cytosol of plants (ppa 1 plants) leads to a decrease of inorganic pyrophosphate (PPi; U. Sonnewald, 1992, Plant J 2: 571-581) [15].

Associations of ppa with chemical compounds

• Inorganic pyrophosphatase (IPP) is an essential enzyme that plays a pivotal role in a broad spectrum of cellular biosynthetic reactions such as amino acid, nucleotide, polysaccharide, and fatty acid biosynthesis [16].
• Reasons for this unexpectedly efficient conversion of sucrose to starch in the ppa 1 tubers were investigated [15].
• Over-expression of PPase resulted in an accumulation of sucrose and UDP-glucose, and decreased concentrations of hexose phosphates and glycerate-3-phosphate in growing ppa 1 tubers [15].
• An inorganic pyrophosphatase was purified over 600-fold to homogeneity as judged by polyacrylamide gel electrophoresis [17].
• Use of biotinylated inorganic pyrophosphatase for detection of biotin bound to solid support [18].

Other interactions of ppa

• The distal portion of chpBK was found to be adjacent to the ppa gene that encodes pyrophosphatase, whose map position had not been previously determined [19].

Analytical, diagnostic and therapeutic context of ppa

• A site-directed mutagenesis study on Escherichia coli inorganic pyrophosphatase. Glutamic acid-98 and lysine-104 are important for structural integrity, whereas aspartic acids-97 and -102 are essential for catalytic activity [20].
• Genetic engineering of Escherichia coli inorganic pyrophosphatase. Tyr55 and Tyr141 are important for the structural integrity [21].
• Regenerated plants were tested for the expression of the ppa gene by Northern blots and activity gels [7].
• Genome sequence analyses revealed the occurrence of two paralogous ppa genes potentially encoding distinct Family I inorganic pyrophosphatases (sPPases, EC3.6.1.1) in the marine unicellular cyanobacteria Prochlorococcus marinus strains MED4 and MIT9313 and Synechococcus sp. WH8102 [3].
• The ppa gene was cloned from B. lactofermentum chromosomal DNA by polymerase chain reaction; it seemed to be an essential gene and it might represent an attractive target for drug discovery [22].

References