Evolutionary conservation of the active site of soluble inorganic pyrophosphatase.
Soluble inorganic pyrophosphatases (PPases) are essential enzymes that are important for controlling the cellular levels of inorganic pyrophosphate (PPi). Although prokaryotic and eukaryotic PPases differ substantially in amino acid sequence, recent evidence now demonstrates clearly that PPases throughout evolution show a remarkable level of conservation of both an extended active site structure, which has the character of a mini-mineral, and a catalytic mechanism. PPases require several (three or four) Mg2+ ions at the active site for activity and many of the 15-17 fully conserved active site residues are directly involved in the binding of metal ions. Each of the eight microscopic rate constants that has been evaluated for the PPases from both Escherichia coli and Saccharomyces cerevisiae is quite similar in magnitude for the two enzymes, supporting the notion of a conserved mechanism.
Cooperman
B S
BS
Department of Chemistry, University of Pennsylvania, Philadelphia 19104.
Baykov
A A
AA
Lahti
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000201:enzymology; D001665:Binding Sites / Q000235:genetics*; D005075:Biological Evolution; D043564:Inorganic Pyrophosphatase; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D011755:Pyrophosphatases / Q000235:genetics*; D012160:Retina / Q000201:enzymology; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D012689:Sequence Homology, Nucleic Acid; D013329:Structure-Activity Relationship
D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase