Pseudomonas aeruginosa esterase PA2949, a bacterial homolog of the human membrane esterase ABHD6: expression, purification and crystallization

Acta Crystallogr F Struct Biol Commun. 2019 Apr 1;75(Pt 4):270-277. doi: 10.1107/S2053230X19002152. Epub 2019 Apr 2.


The human membrane-bound α/β-hydrolase domain 6 (ABHD6) protein modulates endocannabinoid signaling, which controls appetite, pain and learning, as well as being linked to Alzheimer's and Parkinson's diseases, through the degradation of the key lipid messenger 2-arachidonylglycerol (2-AG). This makes ABHD6 an attractive therapeutic target that lacks structural information. In order to better understand the molecular mechanism of 2-AG-hydrolyzing enzymes, the PA2949 protein from Pseudomonas aeruginosa, which has 49% sequence similarity to the ABHD6 protein, was cloned, overexpressed, purified and crystallized. Overexpression of PA2949 in the homologous host yielded the membrane-bound enzyme, which was purified in milligram amounts. Besides their sequence similarity, the enzymes both show specificity for the hydrolysis of 2-AG and esters of medium-length fatty acids. PA2949 in the presence of n-octyl β-D-glucoside showed a higher activity and stability at room temperature than those previously reported for PA2949 overexpressed and purified from Escherichia coli. A suitable expression host and stabilizing detergent were crucial for obtaining crystals, which belonged to the tetragonal space group I4122 and diffracted to a resolution of 2.54 Å. This study provides hints on the functional similarity of ABHD6-like proteins in prokaryotes and eukaryotes, and might guide the structural study of these difficult-to-crystallize proteins.

Keywords: ABHD6; Alzheimer's disease; PA2949; Parkinson's disease; Pseudomonas aeruginosa; endocannabinoid signalling pathway; esterases.

MeSH terms

  • Amino Acid Sequence
  • Crystallization
  • Enzyme Stability
  • Esterases / chemistry*
  • Esterases / isolation & purification*
  • Humans
  • Kinetics
  • Monoacylglycerol Lipases / chemistry*
  • Pseudomonas aeruginosa / enzymology*
  • Sequence Homology, Amino Acid*
  • Substrate Specificity
  • Temperature


  • Esterases
  • ABHD6 protein, human
  • Monoacylglycerol Lipases