Methyltransferases (MTs) constitute a large group of enzymes that catalyze the transfer of a methyl moiety, most frequently from S-adenosyl-L-methionine, to their substrates. It plays an essential role in regulation of gene expression and synthesis of many natural compounds. Owing to its broad substrate spectrum, MTs make important contributions to diversify the spectrum of products through methylation modifications. Recently, great progress has been made in application of MTs for the biosynthesis of various natural products including phenylpropane compounds, fragrances, hormones and antibiotics, which is summarized in this review. Moreover, we highlighted the strategies of using MTs for efficient production and for expanding the diversity of these methylated natural products, and discussed the current challenges and future prospects in this area.
Biological Products ; Methylation ; Methyltransferases/metabolism*

Inflammatory cytokines can mediate many biological processes and are tightly regulated by the body. Loss of control can trigger a range of diseases such as autoimmune inflammation and cancer. Therefore, a number of biological agents that can effectively regulate the biological effects of inflammatory cytokines such as recombinant anti-inflammatory cytokines, cytokine receptors and neutralizing antibodies have been extensively used in the treatment of related diseases caused by the imbalance of inflammatory cytokines. In recent years, in particular, a number of new innovative biological agents for blocking and regulating cytokine activities are emerging. In this article, we review the recent development and clinical use of the biologics targeting TNF-α, IL-1, IL-6 and IL-17, and point out their inherent limitations and clinical risks. Finally, based on the research findings of our own and other scholars, we suggest some approaches and methods for reducing their side-effects and clinical risk. We consider that using modern biotechnology to improve the tissue specificity to inflammatory site and tumor will be an important development direction of such biologics.
Biological Products ; metabolism ; Cytokines ; Humans ; Inflammation

Streptomyces are major sources of bioactive natural products. Genome sequencing reveals that Streptomyces have great biosynthetic potential, with an average of 20-40 biosynthetic gene clusters each strain. However, most natural products from Streptomyces are produced in low yields under regular laboratory cultivation conditions, which hamper their further study and drug development. The production of natural products in Streptomyces is controlled by the intricate regulation mechanisms. Manipulation of the regulatory systems that govern secondary metabolite production will strongly facilitate the discovery and development of natural products of Streptomyces origin. In this review, we summarize progresses in pathway-specific regulators from Streptomyces in the last five years and highlight their role in improving the yields of corresponding natural products.
Biological Products ; Multigene Family ; Secondary Metabolism ; Streptomyces/genetics*

Ubiquitin-Protein Ligases/metabolism* ; Proteolysis ; Biological Products ; Ligands

Atherosclerosis (AS) is an invisible killer among cardiovascular diseases (CVD), which has seriously threatened the life of quality. The complex pathogenesis of AS involves multiple interrelated events and cell types, such as macrophages, endothelial cells, vascular smooth muscle cells and immune cells. Currently, the efficacy of recommended statin treatment is not satisfactory. Natural products (NPs) have attracted increasing attention with regard to their broad structural diversity and biodiversity, which makes them a promising library in the demand for lead compounds with cardiovascular protective bio-activity. NPs can preclude the development of AS by regulating lipid metabolism, ameliorating inflammation, stabilizing plaques, and remodeling the gut microbiota, which lays a foundation for the application of NPs in clinical therapeutics.
Humans ; Biological Products/metabolism* ; Endothelial Cells/metabolism* ; Atherosclerosis/metabolism* ; Macrophages/metabolism* ; Inflammation/metabolism*

Cyclodipeptide (CDP) composed of two amino acids is the simplest cyclic peptide. These two amino acids form a typical diketopiperazine (DKP) ring by linking each other with peptide bonds. This characteristic stable ring skeleton is the foundation of CDP to display extensive and excellent bioactivities, which is beneficial for CDPs' pharmaceutical research and development. The natural CDP products are well isolated from actinomycetes. These bacteria can synthesize DKP backbones with nonribosomal peptide synthetase (NRPS) or cyclodipeptide synthase (CDPS). Moreover, actinomycetes could produce a variety of CDPs through different enzymatic modification. The presence of these abundant and diversified catalysis indicates that actinomycetes are promising microbial resource for exploring CDPs. This review summarized the pathways for DKP backbones biosynthesis and their post-modification mechanism in actinomycetes. The aim of this review was to accelerate the genome mining of CDPs and their isolation, purification and structure identification, and to facilitate revealing the biosynthesis mechanism of novel CDPs as well as their synthetic biology design.
Actinobacteria/metabolism* ; Actinomyces/metabolism* ; Biological Products/metabolism* ; Bacteria/metabolism* ; Diketopiperazines/metabolism* ; Amino Acids

Tyrosine-decahydrofluorene derivatives are a class of hybrid compounds that integrate the properties of polyketides and nonribosomal peptides. These compounds feature a [6.5.6] tricarbocyclic core and a para-cyclophane ether moiety in their structures and exhibit anti-tumor and anti-microbial activities. In this study, we constructed the biosynthetic pathway of xenoacremones from Xenoacremonium sinensis ML-31 in the Aspergillus nidulans host, resulting in the identification of four novel tyrosine-decahydrofluorene analogs, xenoacremones I-L (1-4), along with two known analogs, xenoacremones A and B. Remarkably, compounds 3 and 4 contained a 12-membered para-cyclophane ring system, which is unprecedented among tyrosine-decahydrofluorene analogs in X. sinensis. The successful reconstruction of the biosynthetic pathway and the discovery of novel analogs demonstrate the utility of heterologous expression strategy for the generation of structurally diverse natural products with potential biological activities.
Aspergillus nidulans/metabolism* ; Biological Products/metabolism* ; Polyketides/metabolism* ; Peptides/metabolism* ; Biosynthetic Pathways ; Multigene Family

Constitutively expression of the pathway-specific activators is an effective method to activate silent gene clusters and improve natural product production. In this study, nine shunt products of aminoansamycins (1-9) were identified from a recombinant mutant strain S35-LAL by overexpressed the large-ATP-binding regulator of the LuxR family (LAL) gene aas1 in Streptomyces sp. S35. All the compounds showed no anti-microbial, anti-T3SS and cytotoxic activities.
Biological Products/metabolism* ; Lactams, Macrocyclic/metabolism* ; Multigene Family ; Organisms, Genetically Modified ; Streptomyces/metabolism*

Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin: flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN). Flavoproteins are involved in a wide array of biological processes, such as photosynthesis, DNA repair and natural product biosynthesis. It should be noted that 5%-10% of flavoproteins have a covalently linked flavin prosthetic group. Such covalent linkages benefit the holoenzyme in several ways including improving the stability and catalytic potency. During the past decade, significant progress has been made in covalent flavoproteins, especially with respect to enzyme-dependent biogenesis and discovery of novel linkage types. The present review gives a condensed overview of investigations published from March 2009 to December 2021, with emphasis on the discovery, biogenesis and their catalytic role in natural product biosynthesis.
Flavoproteins/metabolism* ; Flavin-Adenine Dinucleotide/metabolism* ; Flavin Mononucleotide/metabolism* ; Riboflavin ; Biological Products

Yarrowia lipolytica, as an important oleaginous yeast, has been widely used in metabolic engineering. Y. lipolytica is considered as an ideal host for the production of natural products such as terpenes, polyketides and flavonoids, due to its ability to utilize a variety of hydrophobic substrates, high stress tolerance to acid and salt, high flux of tricarboxylic acid cycle and the ability in providing abundant the common precursor acetyl-CoA. Recently, more and more tools for genetic editing, gene expression and regulation has been developed in Y. lipolytica, which facilitate the metabolic engineering of Y. lipolytica for bio-manufacturing. In this review, we summarized the recent progresses in developing gene expression and natural product synthesis in Y. lipolytica, and also discussed the challenges and possible solutions in heterologous synthesis of natural products in this yeast.
Biological Products/metabolism* ; Gene Editing ; Metabolic Engineering ; Polyketides/metabolism* ; Yarrowia/metabolism*