In:
Scientific Reports, Springer Science and Business Media LLC, Vol. 7, No. 1 ( 2017-11-24)
Abstract:
L . pneumophila , an important facultative intracellular bacterium, infects the human lung and environmental protozoa. At least fifteen phospholipases A (PLA) are encoded in its genome. Three of which, namely PlaA, PlaC, and PlaD, belong to the GDSL lipase family abundant in bacteria and higher plants. PlaA is a lysophospholipase A (LPLA) that destabilizes the phagosomal membrane in absence of a protective factor. PlaC shows PLA and glycerophospholipid: cholesterol acyltransferase (GCAT) activities which are activated by zinc metalloproteinase ProA via cleavage of a disulphide loop. In this work, we compared GDSL enzyme activities, their secretion, and activation of PlaA. We found that PlaA majorly contributed to LPLA, PlaC to PLA, and both substrate-dependently to GCAT activity. Western blotting revealed that PlaA and PlaC are type II-secreted and both processed by ProA. Interestingly, ProA steeply increased LPLA but diminished GCAT activity of PlaA. Deletion of 20 amino acids within a predicted disulfide loop of PlaA had the same effect. In summary, we propose a model by which ProA processes PlaA via disulfide loop cleavage leading to a steep increase in LPLA activity. Our results help to further characterize the L . pneumophila GDSL hydrolases, particularly PlaA, an enzyme acting in the Legionella -containing phagosome.
Type of Medium:
Online Resource
ISSN:
2045-2322
DOI:
10.1038/s41598-017-12796-4
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2017
detail.hit.zdb_id:
2615211-3
