A hybrid mutant form of Escherichia coli inorganic pyrophosphatase.
The inorganic pyrophosphatase of Escherichia coli is a tightly hexamer of identical subunits. Upon interaction of its two mutant forms in which the trimer-trimer contacts were weakened because of E20D and H136Q substitutions, a hybrid hexameric E20D/H136Q-PPase is formed. The catalytic activity of its constituent H136Q trimer is same of its hexamer, whereas metal-binding affinity is significantly decreased. These results point to an interdependence of two trimers in catalysis by hexameric pyrophosphatase.
Velichko
I S
IS
Belozersky Institute of Physico-Chemical Biology and School of Chemistry, Lomonosov Moscow State University, Russia.
Baykov
A A
AA
D001665:Binding Sites; D011756:Diphosphates / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology*; D043564:Inorganic Pyrophosphatase; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D011755:Pyrophosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D011756:Diphosphates; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase