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Updated: Jul 15, 2026
Defining Substrate Specificities for Lipase and Phospholipase Candidates
Published on: November 23, 2016
Purification and characterization of mycobacterial phospholipase A: an activity associated with mycobacterial
Sarah K Parker1, Kathryn M Curtin, Michael L Vasil
1Department of Pediatrics, University of Colorado Health Sciences Center, Aurora, CO 80045, USA. sarah.parker@uchsc.edu
Abstract:
We describe mycobacterial phospholipase A activity (MPLA) and, using reverse genetics, have associated this activity with putative mycobacterial cutinase. PLAs, which hydrolyze fatty acids on phospholipids, play a significant role in human inflammatory states and disease pathogenesis. In prokaryotes, the recognition of their role in virulence is more recent. Cutinases are serine esterases whose primary substrate is cutin, the waxy exterior layer of plants. Mycobacterium tuberculosis has maintained seven putative cutinases, though it should not encounter cutin; we demonstrate that known cutinases and MPLA cleave phospholipids in a PLA-type manner and also hydrolyze Tween. We analyzed cutinase motifs in mycobacteria and found the motif very prevalent. All mycobacteria tested had MPLA activity. These studies suggest an alternative use for putative cutinases by the M. tuberculosis group that is likely related to MPLA activity and lipid metabolism.
Insights
Mycobacterial cutinase enzymes, previously thought to act on plant cutin, are shown to possess phospholipase A activity. This discovery reveals a novel role for these enzymes in mycobacterial lipid metabolism and virulence.
Area of Science:
- Biochemistry
- Microbiology
- Enzymology
Background:
- Phospholipase A (PLA) enzymes are crucial in human inflammatory diseases.
- Their role in prokaryotic virulence is a recent area of investigation.
- Mycobacterium tuberculosis possesses seven putative cutinase enzymes.
Purpose of the Study:
- To characterize mycobacterial phospholipase A activity (MPLA).
- To associate MPLA with putative mycobacterial cutinase using reverse genetics.
- To investigate the substrate specificity and prevalence of mycobacterial cutinases.
Main Methods:
- Reverse genetics to link enzyme activity to genes.
- Enzyme assays to measure phospholipase A and Tween hydrolysis.
- Bioinformatic analysis of cutinase motifs in mycobacteria.
Main Results:
- MPLA was identified and associated with mycobacterial cutinase.
- Mycobacterial cutinases were demonstrated to cleave phospholipids like PLAs.
- These enzymes also hydrolyze Tween, a common laboratory lipid.
- Cutinase motifs are prevalent across various mycobacteria, all exhibiting MPLA.
Conclusions:
- Mycobacterial cutinases have a novel function beyond plant cutin hydrolysis.
- This function involves phospholipase A activity, suggesting a role in lipid metabolism.
- The findings offer insights into the virulence mechanisms of Mycobacterium tuberculosis.
