Demonstration and partial characterization of ADP-ribosylation in Pseudomonas maltophilia.
ADP-ribosylation of proteins occurs in many eukaryotes, and it is also the mechanism of action of a growing number of important bacterial toxins. To date, however, there is only one well-characterized ADP-ribosylation system where the ADP-ribosyltransferase and the substrate protein are both bacterial in origin, namely within the nitrogen-fixing bacterium Rhodospirillum rubrum. The present paper demonstrates the endogenous ADP-ribosylation of two proteins of Mr 32,000 and 20,000 within Pseudomonas maltophilia, a Gram-negative aerobe. The proteins have been partially purified: two apparently separate species of modified protein can be separated by ion-exchange chromatography and gel filtration (V0 and Mr 158,000 - Vi). The substrate protein(s) either has, or is co-eluted with, NAD+ glycohydrolase activity. The modification is mono-ADP-ribosyl in nature. The linkage between the acceptor amino acid and the ADP-ribose moiety is alkali-labile and stable to hydroxylamine, possibly indicating an S-glycosidic bond. The activity appears to be a true ADP-ribosylation reaction and not an NAD+ glycohydrolase activity followed by non-enzymic addition of ADP-ribose to protein. The results presented here indicate that ADP-ribosylation may have a wider significance within prokaryotic systems than previously thought.
Edmonds
C
C
Department of Immunology, St. George's Hospital Medical School, London, U.K.
Griffin
G E
GE
Johnstone
A P
AP
D036002:ADP Ribose Transferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001426:Bacterial Proteins / Q000302:isolation & purification; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D011549:Pseudomonas / Q000201:enzymology*
D001426:Bacterial Proteins; D036002:ADP Ribose Transferases