Dominant negative mutants of ornithine decarboxylase.
Conserved lysines of mouse ornithine decarboxylase were individually mutated to arginines. The mutations at amino acid residues 69, 115, and 169 greatly reduced or abolished enzymatic activity. Lysine 69 is the site of Schiff base formation with the cofactor pyridoxal phosphate; the functional role of the other two lysines essential for activity is not known. Coexpression of wild type ornithine decarboxylase along with the lysine 115 to arginine mutant reduced the activity of the former without diminishing the amount of wild type protein. This form of negative complementation was seen when wild type and mutant protein were coexpressed either by in vitro translation or in bacteria. The data are consistent with the conclusion that a wild type and mutant subunit form a heterodimer that is enzymatically inactive.
Tsirka
S
S
Department of Microbiology, University of California, San Francisco 94143.
Coffino
P
P
D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine; D000518:Eflornithine / Q000494:pharmacology; D015870:Gene Expression; D005796:Genes; D005799:Genes, Dominant; D007700:Kinetics; D008239:Lysine; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009955:Ornithine Decarboxylase / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping
D011994:Recombinant Proteins; D001120:Arginine; D009955:Ornithine Decarboxylase; D008239:Lysine; D000518:Eflornithine