Regioselectivity switches between anthraquinone precursor fissions involved in bioactive xanthone biosynthesis.

Xanthone-based polyketides with complex molecular frameworks and potent bioactivities distribute and function in different biological kingdoms, yet their biosynthesis remains under-investigated. In particular, nothing is known regarding how to switch between the C-C (C-selective) and C-C bond (C-selective) cleavages of anthraquinone intermediates involved in biosynthesizing strikingly different frameworks of xanthones and their siblings. Enabled by our characterization of antiosteoporotic brunneoxanthones, a subfamily of polyketides from FB-2, we present herein the brunneoxanthone biosynthetic gene cluster and the C-selective cleavage of anthraquinone (chrysophanol) hydroquinone leading ultimately to the bioactive brunneoxanthones under the catalysis of BruN (an undescribed atypical non-heme iron dioxygenase) in collaboration with BruM as a new oxidoreductase that reduces the anthraquinone into its hydroquinone using NADPH as a cofactor.

[Interaction between root exudates of medicinal plants and rhizosphere microorganisms and its application in ecological planting of Chinese medicinal materials].

The rhizosphere is an important place for material exchange between medicinal plants and soil. Root exudates are the medium of material and signal exchange between plants and soil and are the key factors in the regulation of rhizosphere microecology. Rhizosphere microorganisms are an important part of the rhizosphere microecology of medicinal plants, and the interaction between root exudates and rhizosphere microorganisms has an important influence on the growth and quality formation of medicinal plants.

Impaired proton pumping in cytochrome c oxidase upon structural alteration of the D pathway.

Cytochrome c oxidase is a membrane-bound enzyme, which catalyses the one-electron oxidation of four molecules of cytochrome c and the four-electron reduction of O(2) to water. Electron transfer through the enzyme is coupled to proton pumping across the membrane. Protons that are pumped as well as those that are used for O(2) reduction are transferred though a specific intraprotein (D) pathway.

Sequence-specific assignments of proton NMR resonance peaks and analysis of secondary structural elements of LC1, a novel antibacterial polypeptide.

LC1 is a type of novel antibacterial polypeptide secreted by a Bacillus subtilis strain. It consists of 47 residues. Using bioengineering, LC1 was expressed in E.