Proteolytic cleavage of Pseudomonas aeruginosa exotoxin A in the presence of lipid bilayers of different composition

FEBS Letters

Nordera, Paola¹  Menestrina, Gianfranco¹ 

[1] CNR-ITC Centro di Fisica degli Stati Aggregati, Via Sommarive 14, I-38050 Povo, Trento, Italy

关键词: ADP-ribosylating toxin;    Translocation;    Enzymatic cleavage;    pH dependence;    Acidic phospholipid;    ETA;    Pseudomonas aeruginosa exotoxin A;    SUV;    small unilamellar vesicles;    LUV;    large unilamellar vesicles;    PC;    phosphatidylcholine;    PA;    phosphatidic acid;    PG;    phosphatidylglycerol;    PI;    phosphatidylinositol;    PS;    phosphatidylserine;    PMSF;    phenylmethylsulfonyl fluoride;   

DOI  :  10.1016/S0014-5793(97)01580-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Pseudomonas aeruginosa exotoxin A (ETA) must be proteolytically nicked by furin at Arg²⁷⁹ before being translocated into the cytosol of target cells. A similar cleavage can also be obtained with trypsin. Using this assay we could show that the interaction with lipid bilayers can strongly influence the extent of nicking. We found that in the presence of vesicles containing negatively charged lipids ETA is cleaved into its two fragments A and B at enzyme concentrations ∼50 times lower, or at pH values higher by 1.5 units, than in the absence of lipids. We suggest that the interaction with the lipid bilayer of the positively charged loop containing Arg²⁷⁹ provides the energy for its partial unfolding and makes it more accessible for proteolysis.

【 授权许可】

Unknown