Iron(II)/α-ketoacid-dependent oxygenases (αKAOs) are enzymes that catalyze the oxidation of unactivated C-H bonds, mainly through hydroxylation.
They are present in many secondary metabolite biosynthesis pathways, including those of non-ribosomal peptides where they are involved in diversification reactions. Among these enzymes, those active towards amino acids and their derivatives are grouped into the Clavaminate Synthase Like (CSL) family. CSL enzymes have high regioselectivity and stereoselectivity, often with strict substrate specificity.
By determining the three-dimensional structure of two lysine-active regiodivergent enzymes, we conducted structural and computational analyses of the CSL family by modelling and classifying active sites.
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Superimposition of crystallographic structures of KDO1 and KDO5 in
complex with lysine
| ASMC hierarchical tree of CSL enzymes.
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Our results strongly suggest that the substrate specificity and high stereoselectivity observed in this family are related to two structural characteristics: a flexible loop (lid) and a sub-pocket, when closed, the lid forms a sub-pocket around the substrate side chain. This dynamic cover is found throughout the family with a variable sequence and length and is associated with a stable and preserved dimeric interface.