Natural product is an important source of small-molecule drugs and probes, but its synthesis is challenging and has attracted lasting attention in the field of organic chemistry. With the continuous advancement of chromatographic techniques for separation and spectroscopic methods for structural analysis, the pace of discovering tiny bioactive natural products is accelerating, concomitantly leading to an increase in the diversity and complexity of the newly identified structures. However, to meet the demand of the quantity for the study of their structure-activity relationships, target identification, in vivo activity evaluation, etc., growing challenges in the requirement for the synthetic efficiency, economy, and scalability of natural products are emerging. Synthetic practices in a chemoenzymatic way have provided multi-dimensional visions for natural product research, which emerged as a hot research topic in recent years. On the one hand, enzymatic catalysis has provided highly efficient and selective synthetic methodologies that would complement traditional synthetic methods. On the other hand, the introduction of enzyme-catalyzed reactions would bring a new mode of strategic design for synthesis, enabling the rapid and diverse synthesis of natural products with high efficiency. In this context, how to integrate the enzyme-catalyzed reactions into the synthesis of natural products is the key to a successful chemoenzymatic synthesis. We herein summarized three roles played by the applications of enzyme-catalyzed reactions in the current practices of chemoenzymatic synthesis of natural products. ①The involvement of biocatalysis would introduce a chiral center or a key functional group into the starting material, or supply complex synthetic precursors (e.g., polysubstituted (hetero)aromatics, chiral pools, etc.) via in vitro enzyme-catalyzed reactions or fermentation, hence advancing the starting line of synthesis; ②Late-stage enzyme-catalyzed chemo-, regio-, and stereoselective modifications of substrates with heavily substituted functional groups or inert positions of complex skeletons; ③The strategic application of enzymatic catalysis as a key carbon-carbon bond-forming step in the construction of the skeleton of natural product. Finally, we have also discussed the current challenges and future trends of the chemoenzymatic synthesis of natural products in three facets, including the design of synthetic strategy, the development of synthetic methods, as well as persons involved in the research. Thus, the integration of interdisciplinary methods and technologies, including chemical synthesis and biocatalysis, would invigorate the synthesis of natural products.

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a major class of peptide natural products that often contain noncanonical amino acids and structural motifs with promising potential as drug leads. One unique structural unit found in RiPPs is the C-terminal S-[(Z)-2-aminoethenyl]-D-cysteine (AviCys) or (2S,3S)-S-[(Z)-2-aminoethenyl]-3-methyl-D-cysteine (AviMeCys). Avi(Me)Cys-containing RiPPs usually exhibit potent antimicrobial or anticancer activities, which strictly require the presence of the C-terminal AviCys motifs. Despite the potential of Avi(Me)Cys-containing RiPPs as drug leads, lack of synthetic methods and biosynthetic systems to access these type of cyclic peptides impede the application of Avi(Me)Cys-containing peptides in medicinal chemistry. In this review, we summarize the current understanding of the biosynthesis of Avi(Me)Cys-containing peptides and the progress made in the development of chemical methods to synthesize Avi(Me)Cys motifs and derivatives. This review contains two following major sections: ① The biosynthetic process of Avi(Me)Cys motifs in the different families of Avi(Me)Cys-containing RiPPs, including lanthipeptides, lipolanthines, linaridins and thioamitides, are introduced with three essential enzymatic steps: first, a cysteine decarboxylase oxidatively decarboxylated the C-terminal cysteine, generating a highly reactive enethiol; subsequently, distinct enzymes catalyze the dehydration of a serine/threonine (Ser/Thr) residue or the dethiolation of a Cys residue in the precursor peptide by incorporating a dehydroalanine (Dha) or dehydrobutyrine (Dhb) residue; finally, a putative cyclase catalyzes the Michael-type addition between the enethiol group and a Dha/Dhb residue to yield the Avi(Me)Cys motif. Detailed enzymatic investigation of these biosynthetic steps are introduced. ② The chemical synthesis of the Avi(Me)Cys building block and their analogues via diverse synthetic methodology, including the radical thiol-yne coupling, the oxidative decarboxylation/decarbonylation, and the condensation of amides with acetals. Overall, further elucidation of the complete biosynthetic pathway for Avi(Me)Cys motifs in related RiPPs, along with advancements in the chemical synthesis of Avi(Me)Cys-containing natural product peptides, will facilitate the effective utilization of these bioactive peptide natural products.

The extensive consumption of fossil oil and the rapid accumulation of greenhouse gas emissions have caused long-term changes in the global climate and environment, sparking widespread interest in society for CO₂ bioconversion technologies as a means to address energy transition and climate change. As a new-generation biorefinery platform based on synthetic biology, the synthetic phototrophic community comprises closely cooperating phototrophic and heterotrophic microorganisms. This community is capable of efficiently converting light energy directly into biomass and a variety of chemicals through mutualistic metabolic division of labor among community members. Synthetic phototrophic community is one of the potential ways to achieve sustainable carbon-negative biomanufacturing, and has attracted widespread attention attributed to its advantages in applicability and robustness. In recent years, with the rapid development of systems biology and synthetic biotechnology, a variety of research efforts have been applied to the design and optimization of synthetic phototrophic communities, achieving stable progress and promoting the understanding of phototrophic community production. In this review, we briefly introduced an overview of the advances and current status of synthetic phototrophic community, including mutualistic mechanisms related to element, energy, and information flow. Subsequently, the unique advantages of phototrophic community were outlined. Meanwhile, recent systems biology approaches of phototrophic community were summarized, such as integrative analysis of multi-omics data, genome-scale metabolic modelling, flux balance analysis and community performance predictive algorithms. We also focused on the design and optimization strategies, such as chassis upgrading, immobilization/compartmentalization techniques, and enhanced internal multilayer regulation of synthetic phototrophic community, as well as the progress of their applications in various fields. Furthermore, we analyzed and discussed the constraints and challenges for the further deployment of synthetic phototrophic community on a larger scale, ranging from photosynthetic carbon production rate, intermediate organic matter selection, external predator invasion, to light distribution under high density cultivation. Finally, the future research strategies and engineering directions of synthetic phototrophic community encompassing semiconductor biohybrids, fine regulation of interspecies interaction and multi-omics community model construction were proposed. We conclude by providing a perspective on the future application scenarios of synthetic phototrophic communities in biochemistry, biomedicine, bioremediation and bioagriculture.

Synthetic biology offers boundless possibilities and revolutionary changes to material fields. One remarkable outcome of interdisciplinary integration of synthetic biology and material science is the development of environmentally friendly polyhydroxyalkanoates (PHAs), which serve as ideal alternatives to petroleum-based plastics. PHAs are a family of linear biopolyesters synthesized by various microorganisms as their intracellular storage materials for energy and carbon sources. With at least 150 various monomers, PHAs exhibit diverse structures, material properties, and applications, collectively known as “PHAomics”. When reprograming microbial genomes via synthetic biology and metabolic engineering, in combination with the feeding of special precursors, tailor-made PHAs with defined structures and varied properties can be synthesized. PHAs has been extensively studied in both academia and industry in the last few decades, leading to the commercialization of some PHAs. Next generation industrial biotechnology (NGIB) based on halophilic Halomonas spp. as chassis has been developed to overcome the limitations of current industrial biotechnology. NGIB offers a long lasting, open and continuous, energy and freshwater-saving bioprocess using low-cost mixed substrates and allows morphology engineering for simplified downstream processing. NGIB facilitates low-cost production of various PHAs in large scale. This review introduces PHAomics and summarizes the diverse properties of PHAs produced via NGIB. It primarily focuses on the composition, structure, and material properties of PHAs, as well as their extensive applications in biodegradable plastics, medical implants, medicine, drug delivery carriers, energy sources, and potential smart materials. Additionally, it covers the strategies and tools for strain engineering and their achievements in the tailor-made biosynthesis of PHA using reprogrammed Pseudomonas spp. and Halomonas spp. Finally, this review discusses strategies on how to further reduce the production cost and improve material properties of PHAs. This review summarizes the progresses on the low-cost customized synthesis of PHA biomaterials by synthetic biology, demonstrating the integration of biology and chemistry.

Glycosylation modifications, extensively present on the surfaces of eukaryotic proteins as a type of post-translational modification, hold significant physiological and pathological implications. The microscopic heterogeneity of natural glycoproteins has led to the emergence of the chemical synthesis of homogeneous glycoproteins with defined structures as a crucial frontier in exploring the structure-function relationships of glycosylation modifications. With the flourishing development of protein synthesis and glycoengineering technologies, various protein ligation and polysaccharide synthesis strategies have been developed, enabling the preparation of glycoproteins containing hundreds of amino acid residues. The development of glycoprotein synthesis strategies primarily revolves around chemical and enzymatic approaches for glycosidic bond formation, leading to effective synthesis schemes such as Lansbury’s aspartic acid acylation, chemical strategies based on glycosyl amino acid building blocks, and glycan remodeling strategies using endoglycosidases and glycosyltransferases. This review will discuss the chemical and enzymatic construction of glycosidic bonds, examining existing strategies for the total synthesis of glycoproteins and semi-synthetic approaches that combine with biological expression methods. It will introduce these strategies’ achievements in synthesizing complex homogeneous glycoproteins with different types of glycosylation modifications, such as those with multiple complex N-glycosylation modifications like HSV gD and those containing long hydrophobic segments like IL-2. Additionally, this review will highlight breakthroughs in understanding the structure-function relationships of glycosylation modifications in various physiological processes through these synthetic complex glycoproteins, including the relationship between glycan chain length and immunogenicity in antigenic glycoproteins, and the mechanisms by which O-GlcNAc regulates synaptic function in neurons. Finally, it will summarize the progress made in glycosidic bond construction, purification strategies, and protein solubility, and point out that further optimization of selectivity and synthetic yield remains a pressing issue in the field of glycoprotein synthesis. The wide application of glycoprotein synthesis technology in developing immunotherapies and understanding the molecular mechanisms of various diseases expands the development directions of synthetic science in the field of life and health, from understanding principles to developing products.

DNA-Encoded Library (DEL) technology, as an emerging means of small molecule drug screening, has become an important and indispensable technology platform for new drug discovery and development. The technology incorporates many advantages from combinatorial chemistry, molecular biology, and chemical bioinformatics, which greatly improve the efficiency of compound library synthesis and screening. Meanwhile, driven by the development of nucleic acid-compatible chemical reactions and high-throughput sequencing technology, DEL technology has made remarkable progress and gradually become a fast, economical, and efficient high-throughput screening platform, and has been more and more widely used in seedling compounds screening by universities, research institutes, and large pharmaceutical companies. The success of a DEL screening relies heavily on the chemical space and structural diversity of the compound libraries, both of which are directly affected by the number of chemical reactions compatible with nucleic acids. Therefore, developing the on-DNA chemical reactions to continuously enrich the chemical toolbox for DEL synthesis and thus enhance the structural diversity and drug potential of the molecules in the libraries has been the focus in this field. In recent years, the number of on-DNA chemical reactions has increased significantly, greatly broadening the scope of chemical reactions available for DEL construction. Meanwhile, a series of novel reaction methods, such as photocatalysis, electrocatalysis, and biosynthesis, have also emerged in the application of on-DNA chemical reactions and further expanded the field that on-DNA chemical reactions can reach. In this paper, we systematically review the metal-catalyzed on-DNA chemical reactions in recent years, including C(sp²)—C(sp²) bond-formation reactions, C(sp³)—C(sp³) bond-formation reactions, C(sp²)—C(sp³) bond-formation reactions, and C(sp²)—X bond-formation reactions; the synthesis of on-DNA privileged heterocycles with single-ring, fused-ring, and spirocyclic rings by using target-oriented synthetic and diversity-oriented synthetic strategies; the research progress of photocatalytic and enzyme-catalyzed on-DNA chemical reactions. However, the current developments in on-DNA reactions also have limitations, such as compatibility with nucleic acids and substrate suitability. In the future, it is important to exploit more robust on-DNA reactions that can proceed under mild conditions, new types of on-DNA reactions, and the combination of high-throughput screening and computer-assisted on-DNA reactions.

Steroids exhibit a range of biological activities and are commonly described as the ‘key to life’ in nature. Steroidal-based medications have emerged as the second largest pharmaceutical category following antibiotics, owing to their remarkable bioactivities such as anti-infective, anti-inflammatory, anti-allergic, and antitumor properties. This category encompasses more than 400 drug compounds, representing approximately 17% of FDA-approved medications. The synthesis of steroidal products continues to attract significant attention due to their diverse bioactivities and physicochemical characteristics in pharmaceutical applications. With the increasing demand for steroidal drugs and the fluctuating availability of sapogenin resources, the use of Mycobacteria to convert inexpensive phytosterols to produce key intermediates for steroid drugs has been established as the most mature and sustainable industrial route. However, the complex structure of steroids, particularly their highly oxygenated skeleton, poses challenges for the well-established semi-synthesis route of complex steroid medications. Recent strides in bioinformatics and genetics have significantly advanced the studies on synthesis of steroidal compounds. This review highlights recent advancements in the synthesis of high-value steroids, including the diverse steroid drug intermediate production via external steroidal modifying enzymes expression in engineered Mycobacteria, chemo-enzymatic synthesis of complex steroids, and yeast-based de novo synthesis. It specifically highlights the significant achievements in the chemo-enzymatic synthesis, which combines the precise site- and stereoselectivity of enzymatic transformations with the efficiency of chemosynthesis, enabling the concise synthesis of complex steroidal products. Recent advancements in chemoenzymatic strategies, especially those involving P450 hydroxylase, 3-sterone-Δ¹-dehydrogenase, reductase, and enzyme cascades, have significantly contributed to the efficient and straightforward synthesis of complex steroid medications. On this basis, the future research opportunities and challenges are also discussed, aiming to provide a reference for the efficient development of more value-added steroid compounds, including the development of new generation steroid intermediates, the discovery of novel steroid biocatalysts, and the establishment of steroid synthesis pathways in mycobacteria.

Advances in science and technology are creating huge benefits and value for society. The digitalization of the world has brought great changes to human being’s daily life. Meanwhile, the increasing degree of digitalization has led to an unprecedented explosion of data, resulting in increasingly severe information storage challenges. According to the current developing trend, the global data volume is expected to reach 175 zettabytes by 2025. With the rapid growth of global data volume and the exponential growth of total data, the existing storage methods will no longer be able to meet the storage needs brought by the digitalization of the world and then there is an urgent need to develop information storage methods with better storage performance, higher storage efficiency and more durable storage media. Nature has offered a powerful solution by using DNA molecules as carriers of information, where genetic information has been transferred stably more than a million years. DNA storage has many advantages over traditional storage media, including high storage density, potentially low maintenance costs, and ease of synthesis and chemical modification, which make it an ideal alternative for information storage. The current process of storing data in DNA includes six main steps: encoding, writing, preservation, retrieval, reading, and decoding. Among them, the writing of data is the basic for realizing the storage of data in DNA, concluding writing data in DNA sequence and in DNA structure. In this review, we first introduce strategies for in vivo data writing in DNA storage systems, which primarily involve writing data into DNA sequences and DNA structures. This is followed by an overview of the development of in vivo writing techniques in DNA storage systems. Finally, we discuss the challenges faced by DNA storage systems in terms of high writing costs and slow writing speeds, and prospects for large-scale synthesis of high-purity DNA and improved biocatalysts.

Human early embryonic development is critical for a healthy fetus birth. However, the specific molecular regulatory mechanisms of lineage development, cell fate decisions and embryonic patterning are still shrouded in mystery. Our knowledge about early human embryogenesis has been greatly improved with the recent progress in in vitro culture conditions for human blastocysts and the advancements in omics technology. However, ethical and technological challenges continue to pose obstacles in these studies. With the rapid development of human pluripotent stem cells, they can be coaxed to form embryo-like structures that mimic early human embryonic development in vitro, termed “embryo models”. Interest in human embryonic development has been reinvigorated with the continuing advances in this area. Human embryo models can be divided into two categories "non-integrated embryo models" and “integrated embryo models” according to the different cellular components they possessed. Integrated embryo models represent the embryo-like structures containing both embryonic and extra-embryonic cell types, including blastoids, human extra-embryoids (hEEs), E-assembloids, stem-cell-derived synthetic whole embryo models (SEMs), peri-gastruloids, bilaminiods and heX-embryoids. While non-integrated embryo models sometimes lack the extra-embryonic tissues, including embryoid bodies (EBs), gastruloids, micro-patterned colonies, post-implantation amniotic sac embryoids (PASE). Besides, non-human primate cynomolgus monkey models have greatly expanded our knowledge towards human developmental biology. In this review, we summarized recent human stem cell-based non-integrated and integrated embryo models, and pointed out the technical challenges remained with proposed future directions. These findings lay an important foundation for understanding early human embryonic development, promoting research into human stem cells and their application, as well as preventing and treating early pregnancy loss or congenital diseases. On the other hand, embryo-like structures derived from human stem cell-based integrated embryo models, although do not fully, almost recapitulate the key events and structural organization of the in vivo counterparts, thus eliciting a serious compact on traditional ethical and practical concerns. In the future, non-integrated human embryo models and non-human primate models, which pose fewer ethical challenges, may provide a straightforward way to study the human early embryonic development.

The liver plays an important role in maintaining normal physiological activities of the human body. It has a complex structure and multiple functions, including blood glucose regulation, protein synthesis, detoxification and drug metabolism. Although traditional two-dimensional cell culture and animal models have been used to study liver physiology or pathology, there are still some limitations in truly reflecting the microenvironment of human liver and its response to drugs. The development of liver models in vitro is essential for disease research and effective drug testing. Organ-on-a-chip is a groundbreaking technology that has emerged in recent years by merging engineering and biological approaches. It can replicate the essential structural and functional features of human tissues and organs in vitro. Recently, in vitro liver tissue models created with organ chips have shown an impressive ability to closely mimic the liver tissue microenvironment and offer high-throughput capabilities. These models have been extensively applied in liver regenerative medicine, disease research, and drug testing, highlighting their significant potential in the biomedical field. Therefore, in this paper, we provide a comprehensive overview of the limitations inherent in traditional liver in vitro models, particularly in their ability to replicate complex physiological microenvironments and accurately reproduce liver-specific functions. It delineates the design strategies, technical characteristics, and research advancements associated with novel liver in vitro models, with a particular emphasis on organ-on-a-chip technologies. The discussion focuses on the key elements crucial for the biomimetic construction of liver organ-on-a-chip systems and the simulation of liver tissue microenvironments. These elements include the integration of multicellular components, the replication of liver sinusoid and lobule structures, the establishment of biochemical factor gradients, and the incorporation of fluid dynamics. Moreover, it provides an outlook on the future development of highly physiologically relevant liver organ-on-a-chip and microphysiological systems, considering the integration of advanced techniques such as organoids, biomaterials, and gene editing.