摘要
Summary of main observation and conclusion Thiopeptides,arising from complex posttranslational modifications of a genetically encoded precursor peptide,are of great interest due to their structural complexity and important biological activities.All of these antibiotics share a macrocyclic peptidyl core that contains a central,six-membered nitrogen heterocycle and are classified into five series a-e based on the oxidation state of the central nitrogenous ring.Here,we report that the biosynthesis of the central piperidine heterocycle of series a thiopeptides relies on the activity of homologues of an F420H2-dependent reductase TppX4 by exploiting and characterizing the piperidine-containing thiopeptin biosynthetic gene (tpp)cluster in Streptomyces tateyamensis.In vitro reconstruction of TppX4 activity demonstrated that the piperidine heterocycle of thiopeptins was transformed from a dehydropiperidine heterocycle,and TppX4 tolerated the changes in the C-termini and macrocyclic peptidyl core of substrate and also tolerated dehyropiperidine-containing monocyclic or bicyclic thiopeptides.The identification of TppX4 and its substrate tolerance enriches the biosynthetic toolbox for development of additional thiopeptide analogs for clinical drug screening.
