ADP-RIBOSYLATION OF AN SIMILAR-TO-70-KILODALTON PROTEIN OF KLEBSIELLA-PNEUMONIAE

An similar to 70-kDa protein in the culture supernatant of a human pat hogenic strain of Klebsiella pneumoniae was labeled in the presence of [P-32-adenylate]NAD. Labeling was significantly increased by the addi tion of dithiothreitol (>1 mM) but prevented by treatment of the cultu re supernatant for 3 min at 56 degrees C. The addition of unlabeled NA D, but not of ADP-ribose, blocked labeling of the similar to 70-kDa pr otein, The radioactive label was released by formic acid but not by Hg Cl2 (1 mM) or neutral hydroxylamine (0.5 M), The addition of homogenat es of human platelets, human neutrophils, rat brain, rat lung, or rat spleen tissues to the culture supernatant did not induce labeling of e ukargotic proteins, The data indicate that the K. pneumoniae strain pr oduces ADP-ribosyltransferase which modifies an endogenous protein.