Download MendeleyThe structure of exopolyphosphatase (PPX) from Porphyromonas gingivalis in complex with substrate analogs and magnesium ions reveals the basis for polyphosphate processivity.
Zhang, A., Lu, Z., Xu, Y., Qi, T., Li, W., Zhang, L., Cui, Z.(2021) J Struct Biol 213: 107767-107767
- PubMed: 34214602
- DOI: https://doi.org/10.1016/j.jsb.2021.107767
- Primary Citation of Related Structures:
7EPQ - PubMed Abstract:
The enzymes exopolyphosphatase/guanosine pentaphosphate phosphohydrolase (PPX/GppA) play important roles in the bacterial stringent response. PPX degrades inorganic polyphosphate (polyP), a polymer composed of a few to hundreds of phosphate residues supporting cell survival in the stationary phase. The crystal structure of PPX from Porphyromonas gingivalis (PgPPX) in complex with catalytic magnesium ions and several sulfate ions was solved. PgPPX contained two domains and represented a "closed" configuration. Four sulfate ions forming a linear dispersed chain were observed in the aqueduct of the PPX dimer, which the long polyP chain most likely occupied. The side chain of R255 stretched into the cavity where polyP could be located, obstructing the entrance of larger substrates such as NTP and NDP. This study provided the first view into the structure of the PPX/GppA homolog in complex with magnesium ions and substrate analogs and explained how PgPPX implemented its functionality.
Organizational Affiliation:
Food and Pharmacy College, Xuchang University, China; Key Laboratory of Biomarker Based Rapid-detection Technology for Food Safety of Henan Province, Xuchang University, China.
