Editor: Craig Winstanley
Peptidoglycan lytic activity of the Pseudomonas aeruginosa phage φKZ gp144 lytic transglycosylase
Article first published online: 14 NOV 2006
FEMS Microbiology Letters
Volume 266, Issue 2, pages 201–209, January 2007
How to Cite
Paradis-Bleau, C., Cloutier, I., Lemieux, L., Sanschagrin, F., Laroche, J., Auger, M., Garnier, A. and Levesque, R. C. (2007), Peptidoglycan lytic activity of the Pseudomonas aeruginosa phage φKZ gp144 lytic transglycosylase. FEMS Microbiology Letters, 266: 201–209. doi: 10.1111/j.1574-6968.2006.00523.x
- Issue published online: 24 NOV 2006
- Article first published online: 14 NOV 2006
- Received 28 September 2006; revised 19 October 2006; accepted 20 October 2006.First published online 14 November 2006.
- Pseudomonas aeruginosa;
- phage φKZ;
- phage lysis;
- lytic transglycosylase
The gp144 endolysin gene from the Pseudomonas aeruginosa phage φKZ was cloned and studies of gp144 expression into Escherichia coli showed host cell lysis. The gp144 protein was purified directly from the culture supernatant and from the bacterial cell pellet and showed in vitro antibacterial lytic activity against P. aeruginosa bacteria and degraded purified peptidoglycan of Gram-negative bacteria. MS analysis identified the gp144 peptidoglycan cleavage site and confirmed a lytic transglycosylase enzyme. Studies of gp144 expression in the presence of sodium azide (NaN3), an inhibitor of the protein export machinery, and into an E. coli MM52 secAts mutant at permissive and restrictive temperatures showed that gp144 was secreted independently of the Sec system. The solution conformation of purified gp144 analyzed by circular dichroism spectroscopy was 61% in α-helical content, and showed a 72% decrease when interacting with dimyristoylphosphatidylglycerol (DMPG), one of the major components of bacterial membranes and less than 10% with dimyristoylphosphatidylcholine (DMPC) found in eukaryotic membranes. Membrane vesicles of DMPG anionic lipids containing calcein indicated that gp144 caused a rapid release of fluorescent calcein when interacting with synthetic membranes. These results indicated that gp144 from φKZ is a lytic transglycosylase capable of interacting with and disorganizing bacterial membranes and has potential as an antipseudomonal in phage therapy.