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  • Expression and site-directed mutagenesis of the catalytic domain of human poly(ADP-ribose)polymerase in Escherichia coli. Lysine 893 is critical for activity.

Expression and site-directed mutagenesis of the catalytic domain of human poly(ADP-ribose)polymerase in Escherichia coli. Lysine 893 is critical for activity.

The Journal of biological chemistry (1990-11-05)
F Simonin, J Ménissier-de Murcia, O Poch, S Muller, G Gradwohl, M Molinete, C Penning, G Keith, G de Murcia
ABSTRACT

Bacterially expressed fusion proteins containing the COOH-terminal domain of the human poly(ADP-ribose)polymerase were analyzed by means of a novel assay, the "activity blot," which allows the detection of transferred polypeptides involved in poly(ADP-ribose) synthesis. Deletion analysis demonstrated that the 40-kDa COOH-terminal region of the enzyme is an autonomous catalytic domain exhibiting both the polymerizing and branching activities in the absence of DNA. Site-directed mutagenesis demonstrated that lysine 893 is essential for these catalytic processes. In addition, sequence similarities obtained with the NAD(P)+ amino acid dehydrogenases suggest that (i) lysine 893 may interact with the substrates of poly(ADP-ribose)polymerase and (ii) the COOH-terminal part of the 40-kDa fragment may also contain a Rossman fold structure.