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Interaction of Escherichia coli inorganic pyrophosphatase active sites
Author(s) -
Avaeva Svetlana,
Grigorjeva Olga,
Mitkevich Vladimir,
Sklyankina Vera,
Varfolomeyev Sergei
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01686-5
Subject(s) - random hexamer , trimer , inorganic pyrophosphatase , chemistry , binding site , active site , stereochemistry , cooperative binding , substrate (aquarium) , pyrophosphatase , protein subunit , mutant , crystallography , biochemistry , dimer , catalysis , enzyme , biology , pyrophosphate , organic chemistry , gene , ecology
Escherichia coli inorganic pyrophosphatase (PPase) is a hexamer of identical subunits. This work shows that trimeric form of PPase exhibits the interaction of the active sites in catalysis. Some trimer subunits demonstrate high substrate binding affinity typical for hexamer whereas the rest of subunits reveal more than 300‐fold substrate affinity decrease. This fact indicates the appearance of negative cooperativity of trimer subunits upon substrate binding. Association of the wild‐type (WT) trimer with catalytically inactive, but still substrate binding mutant trimer into hexameric chimera restores the high activity of the first trimer, characteristic of trimer incorporated in the hexamer of WT PPase. Interaction of PPase active sites suggests that there are pathways for information transmission between the active sites, providing the perfect organization and concerted functioning of the hexameric active sites in catalysis.