Further Studies on the Biosynthesis of Tabtoxin (Wildfire Toxin): Incorporation of [2,3‐¹³C₂]Pyruvate into the β‐Lactam Moiety

Abstract

<jats:title>Abstract</jats:title><jats:p>[2,3‐<jats:sup>13</jats:sup>C<jats:sub>2</jats:sub>]Pyruvic acid (<jats:bold>7</jats:bold>) was synthesized and administered to cultures of <jats:italic>Pseudomonas syringae</jats:italic> pv <jats:italic>tabaci</jats:italic>. C(2) and C(3) of <jats:bold>7</jats:bold> were incorporated as an intact unit into the β‐lactam moiety of tabtoxin (<jats:bold>1</jats:bold>). The result suggests that the biosynthesis of <jats:bold>1</jats:bold> is proceeding in part along the lysine pathway. The labelling pattern in <jats:bold>1</jats:bold> and an incorporation experiment with α,α′‐dideuterated (±)‐2,6‐diaminopimelic acid (<jats:bold>19</jats:bold>) indicate that the branching in the biosynthesis of <jats:bold>1</jats:bold> occurs before lysine is formed.