The synthesis and function of the Escherichia coli hemolysin and related RTX exotoxins.
The RTX group of exotoxins represents a branch of a family of exoproteins produced by Gram-negative bacteria which share the properties of being secreted by a leader-independent pathway and a tandemly-repeated nine-amino-acid sequence that is responsible for calcium binding. The Escherichia coli hemolysin (HlyA) is the prototype for the RTX exotoxin family which includes the leukotoxins of Pasteurella haemolytica and Actinobacillus actinomycetemcomitans and hemolysins from four Gram-negative genera. A review of the genetics, synthesis, export and target cell reactivity of the E. coli hemolysin is given. An evolutionary tree of the RTX toxin family based on amino acid sequence similarity is presented.
Welch
R A
RA
Department of Medical Microbiology and Immunology, University of Wisconsin, Madison 53706.
Forestier
C
C
Lobo
A
A
Pellett
S
S
Thomas
W
W
Rowe
G
G
D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000633:toxicity; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000737:chemistry / Q000633:toxicity; D029968:Escherichia coli Proteins; D005098:Exotoxins / Q000096:biosynthesis / Q000737:chemistry / Q000633:toxicity; D006460:Hemolysin Proteins / Q000096:biosynthesis*; D006801:Humans; D012091:Repetitive Sequences, Nucleic Acid
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D029968:Escherichia coli Proteins; D005098:Exotoxins; D006460:Hemolysin Proteins; C036507:Hlya protein, E coli; C018579:leukotoxin