Interaction of diphtheria toxin fragment A and of elongation factor 2 with cibacron blue.
Diphtheria toxin fragment A interacts with Cibacron blue in solution, although it is not retained by blue Sepharose columns. Difference spectral titration of fragment A with the dye gives a dissociation constant of the order of 10(-5) M and a 1:1 stoichiometry for the complex. In equilibrium dialysis experiments Cibacron blue behaves as a competitive inhibitor of the binding of NAD to diphtheria toxin fragment A. The dye inhibits in a non-competitive way the fragment A-catalysed transfer of ADP-ribose from NAD to elongation factor 2 (EF2). By affinity chromatography on blue Sepharose a binding of EF2 and of ADP-ribosyl-EF2 with the dye is also demonstrated. GDP, GTP and GDP(CH2)P are able to displace EF2 from blue Sepharose.
Dipartimento di Patologia sperimentale, Università di Bologna, Italy.
F
F
Rambelli
M
M
Brigotti
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S
Sperti
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L
Montanaro
D000818:Animals; D004396:Coloring Agents / Q000378:metabolism*; D004167:Diphtheria Toxin / Q000378:metabolism*; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D051381:Rats; D014227:Triazines / Q000378:metabolism*
D004396:Coloring Agents; D004167:Diphtheria Toxin; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D010446:Peptide Fragments; D014227:Triazines; C029795:diphtheria toxin fragment A; C012842:Cibacron Blue F 3GA