Thioether Crosslinkages Created by a Radical SAM Enzyme

Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) and School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan 430071, PR China.
ChemBioChem (Impact Factor: 3.09). 05/2012; 13(8):1097-9. DOI: 10.1002/cbic.201200196
Source: PubMed


Unusually versatile: While the β-carbon thioether linkage in lantibiotics has long been appreciated and is relatively well characterized, a recent publication shows that the unusual sulfur-to-α-carbon thioether crosslinks in subtilosin A are produced by a radical SAM enzyme, AlbA, that contains two [4 Fe-4 S] clusters, thus highlighting the versatility of post-translational modifications in natural product biosynthesis.

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    ABSTRACT: Enzymes in the radical SAM (RS) superfamily catalyze a wide variety of reactions through unique radical chemistry. The characteristic markers of the superfamily include a [4Fe-4S] cluster coordinated to the protein via a cysteine triad motif, typically CX(3)CX(2)C, with the fourth iron coordinated by S-adenosylmethionine (SAM). The SAM serves as a precursor for a 5'-deoxyadenosyl radical, the central intermediate in nearly all RS enzymes studied to date. The SAM-bound [4Fe-4S] cluster is located within a partial or full triosephosphate isomerase (TIM) barrel where the radical chemistry occurs protected from the surroundings. In addition to the TIM barrel and a RS [4Fe-4S] cluster, many members of the superfamily contain additional domains and/or additional Fe-S clusters. Recently characterized superfamily members are providing new examples of the remarkable range of reactions that can be catalyzed, as well as new structural and mechanistic insights into these fascinating reactions.
    Current Opinion in Structural Biology 11/2012; 22(6). DOI:10.1016/ · 7.20 Impact Factor