Tetradecyltrimethylammonium inhibits Pseudomonas aeruginosa hemolytic phospholipase C induced by choline

LIFFOURRENA, AS; MASSIMELLI, MJ; FORRELLAD, MA; LISA, AT; DOMENECH, CE; LUCCHESI, GI

CURRENT MICROBIOLOGY

SPRINGER

Año: 2007 p. 530 - 536

0343-8651

Pseudomonas aeruginosa expresses hemolyticphospholipase C (PlcH) with choline or under phosphatelimitingconditions. PlcH from these conditions were differentlyeluted from the Celite-545 column after applicationof an ammonium sulfate linear reverse gradient. The PlcHfrom supernatants of bacteria grown in the presence ofcholine was eluted with 30% ammonium sulfate and wasmore than 85% inhibited by tetradecyltrimethylammonium.PlcH from supernatants of bacteria grown with succinate andammonium ions in a low-phosphate medium was eluted as apeak with 10% of salt and was less than 10% inhibited bytetradecyltrimethylammonium. PlcH from low phosphatewas purified associated with a protein of 17 kDa. Thiscomplex was dissociated and separated on a Sephacryl S-200column with 1% (w/v) sodium dodecyl sulfate. After thisdissociation, the resulting protein of 70 kDa, correspondingto PlcH, was inhibited by tetradecyltrimethylammonium,showing a protection effect of the accompanying protein.RT-PCR analyses showed that in choline media, the plcHgene was expressed independently of plcR. In low-phosphatemedium, the plcH gene was expressed as a plcHRoperon. Because plcR encodes for chaperone proteins, thisresult correlates with the observation that PlcH fromsupernatants of bacteria grown in the presence of cholinewas purified without an accompanying protein. The consequenceof the absence of this chaperone was thattetradecyltrimethylammonium inhibited the PlcH activity.