eprintid: 18881 rev_number: 16 userid: 1419 dir: disk0/00/01/88/81 datestamp: 2013-06-07 20:46:27 lastmod: 2019-02-02 16:56:29 status_changed: 2013-06-07 20:46:27 type: article metadata_visibility: show item_issues_count: 0 eprint_status: archive creators_name: Gu, L creators_name: Wang, B creators_name: Kulkarni, A creators_name: Geders, TW creators_name: Grindberg, RV creators_name: Gerwick, L creators_name: Hkansson, K creators_name: Wipf, P creators_name: Smith, JL creators_name: Gerwick, WH creators_name: Sherman, DH creators_email: creators_email: creators_email: creators_email: creators_email: creators_email: creators_email: creators_email: pwipf@pitt.edu creators_email: creators_email: creators_email: creators_id: creators_id: creators_id: creators_id: creators_id: creators_id: creators_id: creators_id: PWIPF creators_id: creators_id: creators_id: title: Metamorphic enzyme assembly in polyketide diversification ispublished: pub divisions: sch_as_chemistry full_text_status: public abstract: Natural product chemical diversity is fuelled by the emergence and ongoing evolution of biosynthetic pathways in secondary metabolism. However, co-evolution of enzymes for metabolic diversification is not well understood, especially at the biochemical level. Here, two parallel assemblies with an extraordinarily high sequence identity from Lyngbya majuscula form a Β-branched cyclopropane in the curacin A pathway (Cur), and a vinyl chloride group in the jamaicamide pathway (Jam). The components include a halogenase, a 3-hydroxy-3-methylglutaryl enzyme cassette for polyketide Β-branching, and an enoyl reductase domain. The halogenase from CurA, and the dehydratases (ECH"1s), decarboxylases (ECH"2s) and enoyl reductase domains from both Cur and Jam, were assessed biochemically to determine the mechanisms of cyclopropane and vinyl chloride formation. Unexpectedly, the polyketide Β-branching pathway was modified by introduction of a -chlorination step on (S)-3-hydroxy-3-methylglutaryl mediated by Cur halogenase, a non-haem Fe(ii), α-ketoglutarate-dependent enzyme. In a divergent scheme, Cur ECH"2 was found to catalyse formation of the α,Β enoyl thioester, whereas Jam ECH"2 formed a vinyl chloride moiety by selectively generating the corresponding Β, enoyl thioester of the 3-methyl-4-chloroglutaconyl decarboxylation product. Finally, the enoyl reductase domain of CurF specifically catalysed an unprecedented cyclopropanation on the chlorinated product of Cur ECH"2 instead of the canonical α,Β C ≤ C saturation reaction. Thus, the combination of chlorination and polyketide Β-branching, coupled with mechanistic diversification of ECH"2 and enoyl reductase, leads to the formation of cyclopropane and vinyl chloride moieties. These results reveal a parallel interplay of evolutionary events in multienzyme systems leading to functional group diversity in secondary metabolites. © 2009 Macmillan Publishers Limited. All rights reserved. date: 2009-06-04 date_type: published publication: Nature volume: 459 number: 7247 pagerange: 731 - 735 refereed: TRUE issn: 0028-0836 id_number: 10.1038/nature07870 other_id: NLM NIHMS217307 other_id: NLM PMC2918389 pmcid: PMC2918389 pmid: 19494914 mesh_headings: Cyanobacteria--enzymology mesh_headings: Cyclopropanes--metabolism mesh_headings: Enzymes--biosynthesis mesh_headings: Enzymes--chemistry mesh_headings: Enzymes--metabolism mesh_headings: Evolution, Molecular mesh_headings: Halogenation mesh_headings: Thiazoles--metabolism mesh_headings: Vinyl Chloride--metabolism chemical_names: Cyclopropanes chemical_names: Enzymes chemical_names: Thiazoles chemical_names: curacin A chemical_names: Vinyl Chloride chemical_names: cyclopropane citation: Gu, L and Wang, B and Kulkarni, A and Geders, TW and Grindberg, RV and Gerwick, L and Hkansson, K and Wipf, P and Smith, JL and Gerwick, WH and Sherman, DH (2009) Metamorphic enzyme assembly in polyketide diversification. Nature, 459 (7247). 731 - 735. ISSN 0028-0836 document_url: http://d-scholarship-dev.library.pitt.edu/18881/1/licence.txt