Figure 2.

The proposed biosynthetic route of oxime formation in phosphonocystoximates. HpxV is a 2-oxoglutarate- and ferrous iron-dependent 2AEPn dioxygenase that converts 2AEPn to (S)-1H2AEPn. PcxL and HpxL are FAD- and NADPH-dependent amine oxidases that catalyze 2AEPn or 1H2AEPn oxidation to yield 2-hydroxyiminoethylphosphonic acid (1) and 1-hydroxy-2-hydroxyiminoethylphosphonic acid (3), respectively. Multiple steps are required to convert these oxime-containing intermediates to the final products (dashed-line arrows).