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Ornithine Decarboxylase Encoded By Chlorella Virus Pbcv-1, Tiara A. Morehead,, James R. Gurnon, Byron Adams, Kenneth Nickerson, Lisa A. Fitzgerald, James L. Van Etten
Ornithine Decarboxylase Encoded By Chlorella Virus Pbcv-1, Tiara A. Morehead,, James R. Gurnon, Byron Adams, Kenneth Nickerson, Lisa A. Fitzgerald, James L. Van Etten
Byron Adams
Sequence analysis of the 330-kb genome of chlorella virus PBCV-1 revealed an open reading frame, A207R, which encodes a protein with 37–41% amino acid identity to ornithine decarboxylase (ODC) from many eukaryotic organisms. The a207r gene was cloned and the protein was expressed as a His-A207R fusion protein in Escherichia coli. The recombinant protein catalyzes pyridoxal 5’-phosphate-dependent decarboxylation of ornithine to putrescine, the first step in the polyamine biosynthetic pathway The enzyme has a pH optimum of 9.0 and a temperature optimum of 42°C, and it requires dithiothreitol for maximal activity. The enzyme has a Km, for ornithine of 0.78 …