ISSN:
0887-3585
Keywords:
Pseudomonas toxin
;
x-ray crystallography
;
ADP-ribosyl transferase
;
sequence homology
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Pseudomonas aeruginosa exotoxin A is representative of a class of enzymes, the monoADP-ribosyl, which catalyze the covalent transfer of an ADP-ribose moiety of NAD+ to a target substrate. Availability of the three-dimensional structure of exotoxin A provides the opportunity for mapping substrate binding sites and suggesting which amino acid residues may be involved in catalysis. Data from several sources have been combined to develop a proposal for the NAD+ binding site of exotoxin A: the binding of NAD+ fragments adenosine, AMP, and ADP have been delineated crystallographically to 6.0, 6.0, and 2.7 Å, respectively; significant sequence homology spanning 60 residues has been found between exotoxin A and diphtheria toxin, which has the identical enzymatic activity; iodination of exotoxin A, under conditions in which only tyrosine 481 is iodinated in the enzymatic domain, abolishes ADP-ribosyl transferase activity.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prot.340030303
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