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Updated: Mar 17, 2026

Assaying for Inorganic Polyphosphate in Bacteria
Published on: January 21, 2019
Putative binding mode of Escherichia coli exopolyphosphatase and polyphosphates based on a hybrid in
Cristhian Boetsch1, Daniel R Aguayo-Villegas2, Fernando D Gonzalez-Nilo2
1Departamento de Biología Molecular, Facultad de Ciencias Exactas Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina.
Abstract:
The exopolyphosphatase of Escherichia coli processively and completely hydrolyses long polyphosphate chains to ortho-phosphate. Genetic surveys, based on the analysis of single ppx(-) or ppk(-) mutants and on the double mutant, demonstrate a relationship between these genes and the survival capacity. The exopolyphosphatase belongs to the ASKHA protein superfamily, hence, its active site is well known; however, the knowledge of the way in which this enzyme binds polyP remains incomplete. Here we present different computational approaches, site-direct mutagenesis and kinetic data to understand the relationship between structure and function of exopolyphosphatase. We propose H(378) as a fundamental gatekeeper for the recognition of long chain polyphosphate.
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