Interaction of Escherichia coli inorganic pyrophosphatase active sites

FEBS Letters

Mitkevich, Vladimir¹  Sklyankina, Vera¹  Varfolomeyev, Sergei¹  Grigorjeva, Olga¹  Avaeva, Svetlana² 

[1] Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119899, Russia;A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119899, Russia

关键词: Inorganic pyrophosphatase;    Hexameric form;    Trimeric form;    Kinetics;    Cooperativity;   

DOI  :  10.1016/S0014-5793(99)01686-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown