Non-Heme Iron Enzymes Catalyze Heterobicyclic and Spirocyclic Isoquinolone Core Formation in Piperazine Alkaloid Biosynthesis.

We report the discovery and biosynthesis of new piperazine alkaloids-arizonamides, and their derived compounds-arizolidines, featuring heterobicyclic and spirocyclic isoquinolone skeletons, respectively. Their biosynthetic pathway involves two crucial non-heme iron enzymes, ParF and ParG, for core skeleton construction. ParF has a dual function facilitating 2,3-alkene formation of helvamide, as a substrate for ParG, and oxidative cleavage of piperazine.

Prevalence of hepatitis B virus infection in health checkup participants: a cross-sectional study at University Medical Center, Ho Chi Minh City, Vietnam.

Objectives: Vietnam is one of the countries in highly endemic areas of hepatitis B virus (HBV) infection in the world. Our study aims to determine the prevalence of HBV infection among different age groups of workers who had been included for annual general health checkups.

Methods: This cross-sectional study was conducted at the Health Screening Department, University Medical Center at Ho Chi Minh City, Vietnam, using anonymous data from employees who had health checkups from June 2017 to June 2018.

The Biosynthetic Gene Cluster of Mushroom-Derived Antrocin Encodes Two Dual-Functional Haloacid Dehalogenase-like Terpene Cyclases.

(-)-Antrocin (1), produced by the medicinal mushroom Antrodia cinnamomea, is a potent antiproliferative compound. The biosynthetic gene cluster of 1 was identified, and the pathway was characterized by heterologous expression. We characterized a haloacid dehalogenase-like terpene cyclase AncC that biosynthesizes the drimane-type sesquiterpene (+)-albicanol (2) from farnesyl pyrophosphate (FPP).

Biosynthesis of Piperazine-Derived Diazabicyclic Alkaloids Involves a Nonribosomal Peptide Synthetase and Subsequent Tailoring by a Multifunctional Cytochrome P450 Enzyme.

Piperazine-derived diazabicycles are privileged structures found in natural products and synthetic chemical entities, including therapeutic agents. Herein, we deciphered the biosynthesis of two unique classes of diazabicyclic alkaloids, fischerazines A-C. Notably, we characterized a multifunctional P450 monooxygenase NfiC that installs -dihydroxyl groups on the dibenzyl-piperazines, in turn triggering a range of NfiC-catalyzed and spontaneous cyclization events.

Enzyme-Catalyzed Azepinoindole Formation in Clavine Alkaloid Biosynthesis.

(-)-Aurantioclavine (), which contains a characteristic seven-membered ring fused to an indole ring, belongs to the azepinoindole class of fungal clavine alkaloids. Here we show that starting from a 4-dimethylallyl-l-tryptophan precursor, a flavin adenine dinucleotide (FAD)-binding oxidase and a catalase-like heme-containing protein are involved in the biosynthesis of . The function of these two enzymes was characterized by heterologous expression, characterization, and deuterium labeling experiments.