Structure Pseudomonas aeruginosa exotoxin

Wilson BA, Collier RJ (1992) Diphtheria toxin and Pseudomonas aeruginosa exotoxin A Active-site structure and enzymatic mechanism. In Curr. Top. Microbiol. Immunol. 175 27-41. 

Unlike diphtheria toxin, little is known about the structures required for the translocation of the enzymatic subunit of PT. In diphtheria toxin and Pseudomonas aeruginosa exotoxin A, the B moiety can be clearly subdivided into two distinct domains, one responsible for receptor binding, composed essentially of (3 sheets, and one responsible for translocation of the A subunits, essentially composed of a helices (Allured etal., 1986 Choe etal., 1992). There is no clear translocation domain in PT, and much less is known about the internalization step of PT, compared to diphtheria toxin and exotoxin A. 

Wick MJ, Hamood AN, Iglewski BH (1990) Analysis of the structure-function relationship of Pseudomonas aeruginosa exotoxin. A. Mol Microbiol 4 527—535. 

Allured VS, Collier RJ, Carroll SF, etal. (1986) Structure of exotoxin A of Pseudomonas aeruginosa at 3.0-Angstrom resolution. In Proc. Natl. Acad. Sci. USA 83 1320-1324. 

Photolabeling with enzyme substrates, effectors, or photolabile analogs thereof is one of the most useful means of identifying active site residues within the primary structures of enzymes. We have recently applied this method to the study of the NAD-bind-ing sites of two mono(ADP-ribosyl) transferases, diphtheria toxin (DT) and exotoxin A (PT) from Pseudomonas aeruginosa. Both toxins (after appropriate activation steps) transfer ADP-ribose from NAD to elongation factor 2, and as a side reaction, catalyze the hydrolysis of NAD to ADP-ribose, nicotinamide, and a proton. 

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