Answers are grounded in this paper and cite their sources.
The key steps of the biosynthesis of penicillin have now been visualized through X-ray structure determinations of isopenicillin N synthase (IPNS) complexed with the substrate, the product, and close analogues of intermediates. Starting from a linear tripeptide a single non-heme enzyme catalyzes the double cyclization (see picture; AA=aminoadipoyl).
No takes yet. Share an insight, caveat, or question.
Wolfdieter A. Schenk (2000) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: