Publications by authors named "Zhang Yuan Yan"

Article Synopsis
  • - The study focuses on a newly discovered hybrid polyketide called spirocycline A, generated from a gene cluster that combines modular type I and type II polyketide synthases (PKSs) alongside KAS III enzymes, which is a rare occurrence in bacterial aromatic polyketides.
  • - Spirocycline A's unique structure includes a distinct starter unit, four spirocycles, and a dimer formation, differentiating it from existing aromatic polyketides.
  • - The biosynthesis involves a collaborative effort where the type I PKS synthesizes the starter unit, which is then processed by KAS III and type II PKS to create the aromatic backbone, followed by further modifications by specific redox
View Article and Find Full Text PDF

Phenyl polyenes comprise a small family of bacterial natural products with broad and potent bioactivities, primarily found in actinobacteria. Here we report the discovery of five new phenyl polyene metabolites, maduraflavacins A-E (-), from a rare, marine-derived actinobacteria strain NA03286. The structures of these natural products were determined by NMR spectroscopy, HRESIMS, LC-MS/MS, and chemical derivatization.

View Article and Find Full Text PDF

Cyclic peptides with cyclophane linkers are an attractive compound type owing to the fine-tuned rigid three-dimensional structures and unusual biophysical features. Cytochrome P450 enzymes are capable of catalyzing not only the C-C and C-O oxidative coupling reactions found in vancomycin and other nonribosomal peptides (NRPs), but they also exhibit novel catalytic activities to generate cyclic ribosomally synthesized and post-translationally modified peptides (RiPPs) through cyclophane linkage. To discover more P450-modified multicyclic RiPPs, we set out to find cryptic and unknown P450-modified RiPP biosynthetic gene clusters (BGCs) through genome mining.

View Article and Find Full Text PDF
Article Synopsis
  • * The study outlines the biosynthesis of sordarin, starting with a diterpene cyclase (SdnA) that creates a specific cycloaraneosene framework, which is then modified through a series of oxidation reactions by P450 enzymes.
  • * A novel enzyme known as Diels-Alderase SdnG plays a crucial role in forming the sordarin core structure through an intramolecular Diels-Alder reaction, followed by additional modifications like methyl hydroxylation
View Article and Find Full Text PDF

Four new compounds, asperisocoumarin G (1), asperisocoumarin H (2), (±)-asperisocoumarin I [(±)-3], along with the known pergillin (4) and penicisochroman L (5) were isolated from a mangrove endophytic fungus Aspergillus sp. 085242 by further chemical investigation. The structures of the new compounds, including their absolute configurations, were established by analysis of HR-ESI-MS and NMR spectroscopic data, and ECD calculation.

View Article and Find Full Text PDF

The incidence of tuberculosis is increasing worldwide, especially in developing countries. The prevalence of abdominal tuberculosis has been found to be as high as 12% in people with extrapulmonary tuberculosis. Peritoneal thickening and intestinal adhesions can occur in patients with abdominal tuberculosis.

View Article and Find Full Text PDF

An albinic rice is caused by mutation of threonyl-tRNA synthetase, which is essential for plant development by stabilizing of NEP and PEP gene expressions and chloroplast protein synthesis. Chloroplast biogenesis and development depend on complex genetic mechanisms. Apart from their function in translation, aminoacyl-tRNA synthetases (aaRSs) play additional role in gene expression regulation, RNA splicing, and cytokine activity.

View Article and Find Full Text PDF