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Purification, crystallization and X‐ray crystallographic analysis of a putative exopolyphosphatase from Zymomonas mobilis
Author(s) -
Zhang Aili,
Guo Erhong,
Qian Lanfang,
Tang Nga-Yeung,
Watt Rory M.,
Bartlam Mark
Publication year - 2016
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x16000753
Subject(s) - zymomonas mobilis , crystallization , substrate (aquarium) , resolution (logic) , dimer , enzyme , mutant , crystallography , chemistry , biology , biochemistry , organic chemistry , ethanol , gene , ecology , ethanol fuel , artificial intelligence , computer science
Exopolyphosphatase (PPX) enzymes degrade inorganic polyphosphate (poly‐P), which is essential for the survival of microbial cells in response to external stresses. In this study, a putative exopolyphosphatase from Zymomonas mobilis (ZmPPX) was crystallized. Crystals of the wild‐type enzyme diffracted to 3.3 Å resolution and could not be optimized further. The truncation of 29 amino acids from the N‐terminus resulted in crystals that diffracted to 1.8 Å resolution. The crystals belonged to space group C 2, with unit‐cell parameters a = 122.0, b = 47.1, c = 89.5 Å, α = γ = 90, β = 124.5°. An active‐site mutant that crystallized in the same space group and with similar unit‐cell parameters diffracted to 1.56 Å resolution. One molecule was identified per asymmetric unit. Analytical ultracentrifugation confirmed that ZmPPX forms a dimer in solution. It was confirmed that ZmPPX possesses exopolyphosphatase activity against a synthetic poly‐P substrate.