Prajakta Jadhav, Sudeshna Roy, Xuan Yi Butzin, Nicholas C Butzin
{"title":"Engineering a New SsrA-Based Degradation Tag (LAA-LAA) and a Bacterial Synthetic Oscillator.","authors":"Prajakta Jadhav, Sudeshna Roy, Xuan Yi Butzin, Nicholas C Butzin","doi":"10.1021/acssynbio.4c00612","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00612","url":null,"abstract":"<p><p>The ATP-dependent ClpXP-SspB protease complex is responsible for the degradation of intracellular proteins and is maintained at low levels in <i>Escherichia coli</i> to avoid nonspecific degradation. The rate-limiting step in the protease complex leads to proteolytic queueing, where the proteins form waiting lines, and their overall degradation rate is slowed. Synthetic biologists have leveraged proteolytic queueing to design robust synthetic circuits by tagging proteins with the SsrA tag, an 11-amino acid sequence recognized by the complex. Previous work has demonstrated the binding site of each component of the ClpXP-SspB complex to the SsrA tag. However, the precise component responsible for queueing was unknown. To identify the bottleneck in the complex, we designed different SsrA tag variants depending on the chaperone binding sequences. We further overexpressed each protein in the ClpXP-SspB complex <i>in vivo</i> to determine how an increased amount of each component affects the tagged protein levels. Based on the degradation of the SsrA variants, upon overexpression of each component of the ClpXP-SspB system, evidence supports that ClpX (the ATP-dependent chaperone) is responsible for queueing but not ClpP (the protease) or SspB (the adapter, ATP-independent chaperone). In the process, we identified LAA-LAA, a 6-amino acid ClpX-dependent tag that degraded <i>in vivo</i> faster than the original SsrA tag, AANDENYALAA. We speculated that this high degradation tag could be useful in a dynamic-synthetic circuit, so we modified the well-characterized dual-feedback oscillator by replacing its original SsrA tag with the LAA-LAA tag to form the LAA-LAA-Osc oscillator. Both population and single-cell level experiments show that the new and old oscillators have distinct frequencies. Like the original oscillator, thousands of cells containing the new oscillator could be synchronized by entrainment using an external signal. Thus, the new LAA-LAA-Osc oscillator retains the original oscillator's best characteristics (robustness to fluctuations, a steady oscillation period, and entrainment across 1000s of cells to an external signal) but oscillates at a different frequency.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vikas Upadhyay, Hongxiang Li, Jiachen He, Blake Edward Ocampo, Silas Cook, Huimin Zhao, Costas D Maranas
{"title":"Combining Chemical Catalysis with Enzymatic Steps for the Synthesis of the Artemisinin Precursor Dihydroartemisinic Acid.","authors":"Vikas Upadhyay, Hongxiang Li, Jiachen He, Blake Edward Ocampo, Silas Cook, Huimin Zhao, Costas D Maranas","doi":"10.1021/acssynbio.4c00707","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00707","url":null,"abstract":"<p><p>The supply of artemisinin, the primary antimalarial drug recommended by the World Health Organization (WHO), is limited due to synthesis cost and supply constraints. This study explores novel chemo-enzymatic pathways for the efficient synthesis of dihydroartemisinic acid (DHAA), the penultimate precursor to artemisinin. The key concept here is to leverage the seamless integration of chemical and enzymatic steps for more thoroughly exploring synthesis alternatives. Using novoStoic, a biosynthetic pathway design tool, we identified previously unexplored carbon- and energy-balanced pathways for converting amorpha-4,11-diene (AMPD) to DHAA. For some of the enzymatically catalyzed steps lacking efficient enzymes, chemical catalysis alternatives were proposed and implemented, leading to a hybrid chemo-enzymatic pathway design. The proposed pathway converts AMPD directly to DHAA without going through artemisinic acid (AA), making it a shorter pathway compared with the existing synthesis routes for artemisinin. This effort paves the way for the systematic design of chemo-enzymatic pathways and provides insight into decision strategies between chemical synthesis and enzymatic synthesis steps. It serves as an example of how synthesis pathway design tools can be integrated with human intuition for accelerating retrosynthesis and how AI-based tools can identify and replace human intuitions to automate the decision processes. This can help reduce human-machine interventions and improve the development of future tools for synthesis planning.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Metabolic Engineering of <i>Yarrowia lipolytica</i> for Enhanced De Novo Biosynthesis of Icaritin.","authors":"Wen-Zhuo Sun, Xin Wang, Meng-Yu Fu, Le-Fan Liu, Ping Zhang, Bin-Cheng Yin, Wei-Bing Liu, Bang-Ce Ye","doi":"10.1021/acssynbio.4c00754","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00754","url":null,"abstract":"<p><p>Icaritin (ICT) is a naturally occurring flavonoid compound with notable anticancer properties, recently recognized for its efficacy in treating advanced hepatic carcinoma. Traditional methods of ICT production, including plant extraction and chemical synthesis, face challenges such as low yield and environmental concerns. This study leverages synthetic biology to construct a microbial cell factory using <i>Yarrowia lipolytica</i> for de novo ICT synthesis. We engineered the yeast by integrating the ICT synthesis pathway involving EsPT from <i>Epimedium sagittatum</i> and OsOMTm from <i>Oryza sativa</i>. By optimizing the metabolic pathways, including enhancing the supply of DMAPP via mevalonate pathway modifications, and fine-tuning the expression and catalytic efficiency of EsPT through truncation strategies, we significantly improved ICT yield to 247.02 mg/L─the highest microbial ICT titer reported to date. These findings lay a solid foundation for the large-scale industrial production of ICT and offer valuable insights into the biosynthesis of other flavonoid plant natural products.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Metabolic Engineering of Yarrowia lipolytica for Enhanced De Novo Biosynthesis of Icaritin","authors":"Wen-Zhuo Sun, Xin Wang, Meng-Yu Fu, Le-Fan Liu, Ping Zhang, Bin-Cheng Yin, Wei-Bing Liu* and Bang-Ce Ye*, ","doi":"10.1021/acssynbio.4c0075410.1021/acssynbio.4c00754","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00754https://doi.org/10.1021/acssynbio.4c00754","url":null,"abstract":"<p >Icaritin (ICT) is a naturally occurring flavonoid compound with notable anticancer properties, recently recognized for its efficacy in treating advanced hepatic carcinoma. Traditional methods of ICT production, including plant extraction and chemical synthesis, face challenges such as low yield and environmental concerns. This study leverages synthetic biology to construct a microbial cell factory using <i>Yarrowia lipolytica</i> for de novo ICT synthesis. We engineered the yeast by integrating the ICT synthesis pathway involving EsPT from <i>Epimedium sagittatum</i> and OsOMTm from <i>Oryza sativa</i>. By optimizing the metabolic pathways, including enhancing the supply of DMAPP via mevalonate pathway modifications, and fine-tuning the expression and catalytic efficiency of EsPT through truncation strategies, we significantly improved ICT yield to 247.02 mg/L─the highest microbial ICT titer reported to date. These findings lay a solid foundation for the large-scale industrial production of ICT and offer valuable insights into the biosynthesis of other flavonoid plant natural products.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":"14 4","pages":"1142–1151 1142–1151"},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143842474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elizabeth Vaisbourd, Anat Bren, Uri Alon, David S Glass
{"title":"Preventing Multimer Formation in Commonly Used Synthetic Biology Plasmids.","authors":"Elizabeth Vaisbourd, Anat Bren, Uri Alon, David S Glass","doi":"10.1021/acssynbio.4c00508","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00508","url":null,"abstract":"<p><p>Plasmids are an essential tool for basic research and biotechnology applications. To optimize plasmid-based circuits, it is crucial to control plasmid integrity, including the formation of plasmid multimers. Multimers are tandem repeats of entire plasmids formed by failed dimer resolution during replication. Multimers can affect the behavior of synthetic circuits, especially ones that include DNA-editing enzymes. However, occurrence of multimers is not commonly assayed. Here we survey four commonly used plasmid backbones for occurrence of multimers in cloning (JM109) and wild-type (MG1655) strains of <i>Escherichia coli</i>. We find that multimers occur appreciably only in MG1655, with the fraction of plasmids existing as multimers increasing with both plasmid copy number and culture passaging. In contrast, transforming multimers into JM109 can yield strains that contain no singlet plasmids. We present an MG1655 <i>ΔrecA</i> single-locus knockout that avoids multimer production. These results can aid synthetic biologists in improving design and reliability of plasmid-based circuits.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS Synthetic BiologyPub Date : 2025-03-18DOI: 10.1021/acssynbio.4c0050810.1021/acssynbio.4c00508
Elizabeth Vaisbourd, Anat Bren, Uri Alon and David S. Glass*,
{"title":"Preventing Multimer Formation in Commonly Used Synthetic Biology Plasmids","authors":"Elizabeth Vaisbourd, Anat Bren, Uri Alon and David S. Glass*, ","doi":"10.1021/acssynbio.4c0050810.1021/acssynbio.4c00508","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00508https://doi.org/10.1021/acssynbio.4c00508","url":null,"abstract":"<p >Plasmids are an essential tool for basic research and biotechnology applications. To optimize plasmid-based circuits, it is crucial to control plasmid integrity, including the formation of plasmid multimers. Multimers are tandem repeats of entire plasmids formed by failed dimer resolution during replication. Multimers can affect the behavior of synthetic circuits, especially ones that include DNA-editing enzymes. However, occurrence of multimers is not commonly assayed. Here we survey four commonly used plasmid backbones for occurrence of multimers in cloning (JM109) and wild-type (MG1655) strains of <i>Escherichia coli</i>. We find that multimers occur appreciably only in MG1655, with the fraction of plasmids existing as multimers increasing with both plasmid copy number and culture passaging. In contrast, transforming multimers into JM109 can yield strains that contain no singlet plasmids. We present an MG1655 <i>ΔrecA</i> single-locus knockout that avoids multimer production. These results can aid synthetic biologists in improving design and reliability of plasmid-based circuits.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":"14 4","pages":"1309–1315 1309–1315"},"PeriodicalIF":3.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acssynbio.4c00508","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143842435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS Synthetic BiologyPub Date : 2025-03-18DOI: 10.1021/acssynbio.4c0078510.1021/acssynbio.4c00785
Longhui Huang, Yiduo Zhou, Yamiao Feng, Shiru Jia, Shujun Wang and Cheng Zhong*,
{"title":"Tailoring Bacterial Cellulose through the CRISPR/Cas9-Mediated Gene Editing Tool in Komagataeibacter xylinus","authors":"Longhui Huang, Yiduo Zhou, Yamiao Feng, Shiru Jia, Shujun Wang and Cheng Zhong*, ","doi":"10.1021/acssynbio.4c0078510.1021/acssynbio.4c00785","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00785https://doi.org/10.1021/acssynbio.4c00785","url":null,"abstract":"<p >Bacterial cellulose (BC) is a nanocellulose produced by bacteria, formed by glucose units linked through β-1,4 glycosidic bonds. It features a three-dimensional network structure, superior water retention capacity, high porosity, and outstanding biocompatibility, among other notable characteristics. <i>Komagataeibacter xylinus</i> was the predominant strain used for BC production. The CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR associate-protein 9)-mediated gene editing tool has been applied in various species; however, its application in <i>K. xylinus</i> has not been reported. To facilitate metabolic pathway engineering in <i>K. xylinus</i>, a CRISPR/Cas9-mediated gene editing tool specific to this strain was developed, achieving a gene editing efficiency exceeding 73%. Upon application of the CRISPR/Cas9-mediated gene editing tool in <i>K. xylinus</i>, the strain’s ability to synthesize BC was enhanced by 23.6% (5.75 g/L), and the impact of BC synthase-correlated genes (<i>bcsH</i>, <i>bcsX</i>, <i>bcsY</i>, <i>and bcsZ</i>) on BC structure was investigated. The advancement of CRISPR/Cas9-mediated gene editing tools in <i>K. xylinus</i> is expected to accelerate genetic modification of this organism. This advancement has the potential to significantly improve our understanding of the genetic regulatory mechanisms that govern the structure and production of BC, thereby facilitating cost-effective synthesis of BC with tailored structural properties.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":"14 4","pages":"1161–1172 1161–1172"},"PeriodicalIF":3.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143842441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS Synthetic BiologyPub Date : 2025-03-18DOI: 10.1021/acssynbio.4c0042110.1021/acssynbio.4c00421
Arlinda Rezhdo, Rebecca L. Hershman, Sean J. Williams and James A. Van Deventer*,
{"title":"Design, Construction, and Validation of a Yeast-Displayed Chemically Expanded Antibody Library","authors":"Arlinda Rezhdo, Rebecca L. Hershman, Sean J. Williams and James A. Van Deventer*, ","doi":"10.1021/acssynbio.4c0042110.1021/acssynbio.4c00421","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00421https://doi.org/10.1021/acssynbio.4c00421","url":null,"abstract":"<p ><i>In vitro</i> display technologies, exemplified by phage and yeast display, have emerged as powerful platforms for antibody discovery and engineering. However, the identification of antibodies that disrupt target functions beyond binding remains a challenge. In particular, there are very few strategies that support identification and engineering of either protein-based irreversible binders or inhibitory enzyme binders. Expanding the range of chemistries in antibody libraries has the potential to lead to efficient discovery of function-disrupting antibodies. In this work, we describe a yeast display-based platform for the discovery of chemically diversified antibodies. We constructed a billion-member antibody library, called the “Clickable CDR-H3 Library”, that supports the presentation of a range of chemistries within antibody variable domains via noncanonical amino acid (ncAA) incorporation and subsequent bioorthogonal click chemistry conjugations. Use of a polyspecific orthogonal translation system enables introduction of chemical groups with various properties, including photoreactive, proximity-reactive, and click chemistry-enabled functional groups for library screening. We established conjugation conditions that facilitate modification of the full library, demonstrating the feasibility of sorting the full billion-member library in “protein–small molecule hybrid” format in future work. Here, we conducted initial library screens after introducing <i>O</i>-(2-bromoethyl)tyrosine (OBeY), a weakly electrophilic ncAA capable of undergoing proximity-induced crosslinking to a target. Enrichments against donkey IgG and protein tyrosine phosphatase 1B (PTP1B) each led to the identification of several OBeY-substituted clones that bind to the targets of interest. Flow cytometry analysis on the yeast surface confirmed higher retention of binding for OBeY-substituted clones compared to clones substituted with ncAAs lacking electrophilic side chains after denaturation. However, subsequent crosslinking experiments in solution with ncAA-substituted clones yielded inconclusive results, suggesting that weakly reactive OBeY side chain is not sufficient to drive robust crosslinking in the clones isolated here. Nonetheless, this work establishes a multimodal, chemically expanded antibody library and demonstrates the feasibility of conducting discovery campaigns in chemically expanded format. This versatile platform offers new opportunities for identifying and characterizing antibodies with properties beyond what is accessible with the canonical amino acids, potentially enabling discovery of new classes of reagents, diagnostics, and even therapeutic leads.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":"14 4","pages":"1021–1040 1021–1040"},"PeriodicalIF":3.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143842434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS Synthetic BiologyPub Date : 2025-03-18DOI: 10.1021/acssynbio.4c0083910.1021/acssynbio.4c00839
Luca Ricci*, Xuecong Cen, Yuexuan Zu, Giacomo Antonicelli, Zhen Chen, Debora Fino, Fabrizio C. Pirri, Gregory Stephanopoulos*, Benjamin M. Woolston* and Angela Re*,
{"title":"Metabolic Engineering of E. coli for Enhanced Diols Production from Acetate","authors":"Luca Ricci*, Xuecong Cen, Yuexuan Zu, Giacomo Antonicelli, Zhen Chen, Debora Fino, Fabrizio C. Pirri, Gregory Stephanopoulos*, Benjamin M. Woolston* and Angela Re*, ","doi":"10.1021/acssynbio.4c0083910.1021/acssynbio.4c00839","DOIUrl":"https://doi.org/10.1021/acssynbio.4c00839https://doi.org/10.1021/acssynbio.4c00839","url":null,"abstract":"<p >Effective employment of renewable carbon sources is highly demanded to develop sustainable biobased manufacturing. Here, we developed <i>Escherichia coli</i> strains to produce 2,3-butanediol and acetoin (collectively referred to as diols) using acetate as the sole carbon source by stepwise metabolic engineering. When tested in fed-batch experiments, the strain overexpressing the entire acetate utilization pathway was found to consume acetate at a 15% faster rate (0.78 ± 0.05 g/g/h) and to produce a 35% higher diol titer (1.16 ± 0.01 g/L) than the baseline diols-producing strain. Moreover, singularly overexpressing the genes encoding alternative acetate uptake pathways as well as alternative isoforms of genes in the malate-to-pyruvate pathway unveiled that leveraging <i>ackA-pta</i> and <i>maeA</i> is more effective in enhancing acetate consumption and diols production, compared to <i>acs</i> and <i>maeB</i>. Finally, the increased substrate consumption rate and diol production obtained in flask-based experiments were confirmed in bench-scale bioreactors operated in fed-batch mode. Consequently, the highest titer of 1.56 g/L achieved in this configuration increased by over 30% compared to the only other similar effort carried out so far.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":"14 4","pages":"1204–1219 1204–1219"},"PeriodicalIF":3.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acssynbio.4c00839","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143842439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arlinda Rezhdo, Rebecca L Hershman, Sean J Williams, James A Van Deventer
{"title":"Design, Construction, and Validation of a Yeast-Displayed Chemically Expanded Antibody Library.","authors":"Arlinda Rezhdo, Rebecca L Hershman, Sean J Williams, James A Van Deventer","doi":"10.1021/acssynbio.4c00421","DOIUrl":"10.1021/acssynbio.4c00421","url":null,"abstract":"<p><p><i>In vitro</i> display technologies, exemplified by phage and yeast display, have emerged as powerful platforms for antibody discovery and engineering. However, the identification of antibodies that disrupt target functions beyond binding remains a challenge. In particular, there are very few strategies that support identification and engineering of either protein-based irreversible binders or inhibitory enzyme binders. Expanding the range of chemistries in antibody libraries has the potential to lead to efficient discovery of function-disrupting antibodies. In this work, we describe a yeast display-based platform for the discovery of chemically diversified antibodies. We constructed a billion-member antibody library, called the \"Clickable CDR-H3 Library\", that supports the presentation of a range of chemistries within antibody variable domains via noncanonical amino acid (ncAA) incorporation and subsequent bioorthogonal click chemistry conjugations. Use of a polyspecific orthogonal translation system enables introduction of chemical groups with various properties, including photoreactive, proximity-reactive, and click chemistry-enabled functional groups for library screening. We established conjugation conditions that facilitate modification of the full library, demonstrating the feasibility of sorting the full billion-member library in \"protein-small molecule hybrid\" format in future work. Here, we conducted initial library screens after introducing <i>O</i>-(2-bromoethyl)tyrosine (OBeY), a weakly electrophilic ncAA capable of undergoing proximity-induced crosslinking to a target. Enrichments against donkey IgG and protein tyrosine phosphatase 1B (PTP1B) each led to the identification of several OBeY-substituted clones that bind to the targets of interest. Flow cytometry analysis on the yeast surface confirmed higher retention of binding for OBeY-substituted clones compared to clones substituted with ncAAs lacking electrophilic side chains after denaturation. However, subsequent crosslinking experiments in solution with ncAA-substituted clones yielded inconclusive results, suggesting that weakly reactive OBeY side chain is not sufficient to drive robust crosslinking in the clones isolated here. Nonetheless, this work establishes a multimodal, chemically expanded antibody library and demonstrates the feasibility of conducting discovery campaigns in chemically expanded format. This versatile platform offers new opportunities for identifying and characterizing antibodies with properties beyond what is accessible with the canonical amino acids, potentially enabling discovery of new classes of reagents, diagnostics, and even therapeutic leads.</p>","PeriodicalId":26,"journal":{"name":"ACS Synthetic Biology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}