Division of Chemical Biology and Medicinal Chemistry Eshelman School of Pharmacy, and Lineberger Comprehensive Cancer Center , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27514 , United States.
J Am Chem Soc. 2019 Feb 6;141(5):1842-1846. doi: 10.1021/jacs.8b11852. Epub 2019 Jan 22.
Thiopeptide pyridine synthases catalyze a multistep reaction involving a unique and nonspontaneous intramolecular aza-[4 + 2] cycloaddition between two dehydroalanines to forge a trisubstituted pyridine core. We discovered that the in vitro activity of pyridine synthases from the thiocillin and thiomuracin pathways are significantly enhanced by general base catalysis and that this broadly expands the enzymes substrate tolerance. Remarkably, TbtD is competent to perform an intermolecular cyclization in addition to its cognate intramolecular reaction, underscoring its versatility as a biocatalyst. These data provide evidence that pyridine synthases use a two-site substrate recognition model to engage and process their substrates.
噻肽吡啶合酶催化一个多步骤反应，其中涉及两个去氢丙氨酸之间独特且非自发的分子内氮杂-[4 + 2]环加成，以形成一个三取代吡啶核心。我们发现，来自硫霉素和硫霉素途径的吡啶合酶的体外活性通过广义碱催化得到显著增强，这广泛扩展了酶的底物耐受性。值得注意的是，TbtD 除了能够进行同源的分子内环化反应外，还能够进行分子间环化，突出了其作为生物催化剂的多功能性。这些数据提供了证据，表明吡啶合酶使用双位点底物识别模型来结合和处理它们的底物。
