Biology subjects

Yang, X.

Publications and source records attributed to Yang, X..

At least 343 records · Page 19Linked to original sources

bioRxiv2024

Assessment of drive efficiency and resistance allele formation of a homing gene drive in the mosquito Aedes aegypti

Aedes aegypti, known for transmitting viruses such as dengue, zika, and yellow fever, poses a significant public health threat. Conventional insecticides give rise to a range of issues, including ecological contamination and insect resistance. Hence, there is a pressing demand for environmentally friendly, safer, and more efficacious strategies for mosquito control. With the rapid advancement of the CRISPR/Cas9 system in gene function exploration and pest population control, substantial progress has been achieved in utilizing CRISPR/Cas9-based gene drive systems across various mosquito species. Only a few studies on gene drive technology have been conducted in A. aegypti. In this study, we constructed two complete drives for A. aegypti with different Cas9 promoters, each targeting kmo. Our drive based on Pub-Cas9 had limited activity, but one with exu-Cas9 exhibited super-Mendelian inheritance rates of approximately 60%. We observed low but detectable somatic activity of the drive and no evidence of maternally deposited Cas9. Germline resistance allele formation rates were similar to drive conversion rates, but most wild-type alleles in the germline remained uncut. Injections into the exu-Cas9 drive line had 100% knockout efficiency among surviving offspring at three separate target genes. These results support the development and application of novel genetic pest control technologies aimed at combating A. aegypti.

genetics↗

bioRxiv2024

Genomic mosaicism reveals developmental organization of trunk neural crest-derived ganglia

The neural crest generates numerous cell types, but conflicting results leave developmental origins unresolved. Here using somatic mosaic variants as cellular barcodes, we infer embryonic clonal dynamics of trunk neural crest, focusing on the sensory and sympathetic ganglia. From three independent adult neurotypical human donors, we identified 1,278 mosaic variants using deep whole-genome sequencing, then profiled allelic fractions in 187 anatomically dissected ganglia. We found a massive rostrocaudal spread of progenitor clones specific to sensory or sympathetic ganglia, which unlike in the brain, showed robust bilateral distributions. Computational modeling suggested neural crest progenitor fate specification preceded delamination from neural tube. Single-cell multiomic analysis suggested both neurons and glia contributed to the rostrocaudal clonal organization. CRISPR barcoding in mice and live imaging in quail embryos confirmed these clonal dynamics across multiple somite levels. Our findings reveal an evolutionarily conserved clonal spread of cells populating peripheral neural ganglia. Highlights- Genetic mosaicism and real-time imaging reveal trunk neural crest cellular dynamics. - DRG or SG cells from different axial levels are more lineage-related than from the same level. - Cell fate specification of trunk neural crest progenitors occurs before neural tube delamination. - These aspects of clonal organization are evolutionarily conserved across mammals and avians.

developmental biology↗

bioRxiv2024

Complement therapeutic Factor H-IgG proteins as pre-exposure prophylaxes against Lyme borreliae infections

Lyme disease (LD) is the most common vector-borne disease in the northern hemisphere and is caused by the bacteria Borrelia burgdorferi sensu lato (also known as Lyme borreliae) with no effective prevention available. Lyme borreliae evade complement killing, a critical arm of host immune defense, by producing outer surface proteins that bind to a host complement inhibitor, factor H (FH). These outer surface proteins include CspA and CspZ, which bind to the 6th and 7th short consensus repeats of FH (SCR(6-7)), and the OspE family of proteins (OspE), which bind to the 19th and 20th SCR (SCR19-20). In this study, we produced two chimeric proteins, FH-Fc, containing the Fc region of immunoglobulin G (Fc) with SCR(6-7) or SCR(19-20). We found that both FH-Fc constructs killed B. burgdorferi in the presence of complement and reduced bacterial colonization and LD-associated joint inflammation in vivo. While SCR(6-7)-Fc displayed Lyme borreliae species-specific bacterial killing, SCR(19-20)-Fc versatilely eradicated all tested bacterial species/strains. This correlated with SCR(6-7)-Fc binding to select variants of CspA and CspZ, but SCR(19-20)-Fc binding to all tested OspE variants. Overall, we demonstrated the concept of using FH-Fc constructs to kill Lyme borreliae and defined underlying mechanisms, highlighting the potential of FH-Fc as a pre-exposure prophylaxis against LD infection. AUTHOR SUMMARYTransmitted by ticks, Lyme disease (LD) is the most common vector-borne disease in North America and has experienced an expanded geographical range and increasing number of cases in recent years. No effective prevention is currently available. The causative agent of LD, Borrelia burgdorferi sensu lato (Bbsl), is a complex containing a variety of species. To escape from killing by complement, one of the mammalian host defense mechanisms, Bbsl produces outer surface proteins that bind to a complement inhibitor, factor H (FH). These FH-binding proteins (i.e., CspA, CspZ, and OspE) evade complement by recruiting FH to the bacterial surface. Here we produced two FH-Fc fusion proteins, which combine human immunoglobulin Fc with the human FH domains that bind to Bbsl FH-binding proteins. We found that FH-Fc constructs kill Bbsl in vitro and prevent colonization and LD manifestations in murine models, correlating with these FH-Fc constructs ability to bind to CspA, CspZ, and OspE from respective Bbsl species. These results suggest the possibility of using FH-Fc as a prevention against LD.

microbiology↗

bioRxiv2024

Extracellular phase separation mediates storage and release of thyroglobulin in the thyroid follicular lumen

Thyroid hormones are produced by the thyroid gland and are essential for regulating metabolism, growth and development. Maintenance of circulating thyroid hormone levels within an appropriate range is thus a prerequisite for health. In vivo, this objective is, at least in part, facilitated through an extracellular storage depot of thyroglobulin, the glycoprotein precursor for thyroid hormones, in the thyroid follicular lumen. The molecular basis for how soluble thyroglobulin molecules form such dense depot assemblies remains elusive. Here, we describe in vitro biophysical analysis of thyroglobulin phase behaviour, suggesting that thyroglobulin is prone to undergoing ionic strength-dependent phase separation, leading to the formation of liquid-like condensates. Fluorescence photobleaching measurements further show that these condensates age as a function of time to form reversible gel-like high density storage depots of thyroglobulin. Immunofluorescence experiments on mouse and human thyroid follicles ex vivo reveal that spherical globules of Tg protein dense phase are present in the follicular lumen, consistent with the idea that Tg undergoes phase separation. These findings reveal a molecular mechanism for the last-come-first-served process of thyroglobulin storage and release, suggesting a role for extracellular phase separation in thyroid hormone homeostasis by providing organizational and architectural specificity without requiring membrane-mediated confinement.

biophysics↗

bioRxiv2024

Vascular responses of hypercapnia challenge in mice

Hypercapnia challenge with a few percent of carbon dioxide is popularly used in physiological studies to investigate the dynamic vascular properties. A typical hypercapnia experiment can be divided into four phases: baseline (regular air), transition (CO2 enriched), hypercapnia (CO2 enriched), and recovery (regular air). Cerebrovascular reactivity (CVR), denoting the percentage of functional changes between baseline and hypercapnia phases, can be measured to assess vascular health. In this study, we focus on the transition and recovery phases to track the built-up of cerebral blood flow (CBF) increase induced by CO2-enriched gas and recovery of CBF after returning to regular air. Dynamic features were compared with those of another potent vasodilatory agent, acetazolamide. Our results reveal that 5 min is sufficiently long to ensure 95% built-up of CBF increase under 5% CO2, but it takes much longer to recover to baseline.

physiology↗

bioRxiv2024

Global remodeling of ADP-ribosylation by PARP1 suppresses influenza A virus infection

ADP-ribosylation is a highly dynamic and fully reversible post-translational modification performed by poly(ADP-ribose) polymerases (PARPs) that modulates protein function, abundance, localization and turnover. Here we show that influenza A virus infection causes a rapid and dramatic upregulation of global ADP-ribosylation that inhibits viral replication. Mass spectrometry defined for the first time the global ADP-ribosylome during infection, creating an infection-specific profile with almost 4,300 modification sites on [~]1,080 host proteins, as well as over 100 modification sites on viral proteins. Our data indicate that the global increase likely reflects a change in the form of ADP-ribosylation rather than modification of new targets. Functional assays demonstrated that modification of the viral replication machinery antagonizes its activity and further revealed that the anti-viral activity of PARPs and ADP-ribosylation is counteracted by the influenza A virus protein NS1, assigning a new activity to the primary viral antagonist of innate immunity. We identified PARP1 as the enzyme producing the majority of poly(ADP-ribose) present during infection. Influenza A virus replicated faster in cells lacking PARP1, linking PARP1 and ADP-ribosylation to the anti-viral phenotype. Together, these data establish ADP-ribosylation as an anti-viral innate immune-like response to viral infection antagonized by a previously unknown activity of NS1.

microbiology↗

bioRxiv2024

Cryo-EM Structure of an Active Bacterial SIR2-STAND Filament

Bacterial antiviral STANDs (Avs) are evolutionarily related to the nucleotide-binding leucine-rich repeat containing receptors (NLRs) widely distributed in immune systems across animals and plants. EfAvs5, an Avs type 5 protein from Escherichia fergusonii, contains an N-terminal SIR2 effector domain, a nucleotide-binding oligomerization domain (NOD) and a C-terminal sensor domain, conferring protection against diverse phage invasions. Despite the established roles of SIR2 and STAND in prokaryotic and eukaryotic immunity, the mechanism underlying their collaboration remains unclear. Here we present cryo-EM structures of EfAvs5 filaments, elucidating the mechanisms of dimerization, filamentation, filament clustering, ATP binding and NAD+ hydrolysis, all of which are crucial for anti-phage defense. The SIR2 domains and NODs engage in the intra- and inter-dimer interaction to form an individual filament, while the outward C-terminal domains contribute to bundle formation. Filamentation potentially stabilizes the dimeric SIR2 configuration, thereby activating the NADase activity of EfAvs5. EfAvs5 is deficient in the ATPase activity, but elevated ATP concentrations can impede its NADase activity. Together, we uncover the filament assembly of Avs5 as a unique mechanism to switch enzyme activities and perform anti-phage defenses, emphasizing the conserved role of filamentation in immune signaling across diverse life forms. KeypointsO_LIEfAvs5 depletes NAD+ for anti-phage defense. C_LIO_LIEfAvs5 assembles as bundled filaments that can hydrolyze NAD+. C_LIO_LIThe SIR2 domain and NOD collaborate to form an individual filament. C_LIO_LIThe building block of the filament is EfAvs5 dimer. C_LIO_LIThe activity of the EfAvs5 complex is regulated by ATP. C_LI

microbiology↗

bioRxiv2024

High-speed 4D fluorescence light field tomography of whole freely moving organisms

Volumetric fluorescence imaging techniques, such as confocal, multiphoton, light sheet, and light field microscopy, have become indispensable tools across a wide range of cellular, developmental, and neurobiological applications. However, it is difficult to scale such techniques to the large 3D fields of view (FOV), volume rates, and synchronicity requirements for high-resolution 4D imaging of freely behaving organisms. Here, we present reflective Fourier light field computed tomography (ReFLeCT), a new high-speed volumetric fluorescence computational imaging technique. ReFLeCT synchronously captures entire tomograms of multiple unrestrained, unanesthetized model organisms over multi-millimeter 3D FOVs at 120 volumes per second. In particular, we applied ReFLeCT to reconstruct 4D videos of fluorescently labeled zebrafish and Drosophila larvae, enabling us to study their heartbeat, fin and tail motion, gaze, jaw motion, and muscle contractions with nearly isotropic 3D resolution while they are freely moving. As a novel approach for snapshot tomographic capture, ReFLeCT is a major advance towards bridging the gap between current volumetric fluorescence microscopy techniques and macroscopic behavioral imaging.

animal behavior and cognition↗

bioRxiv2024

Modular Nano-Scaffold Biocatalysis for Superior PET Depolymerization and Valorization

The global crisis of polyethylene terephthalate (PET) waste demands new strategies for sustainable management. Biocatalytic recycling offers a promising route, but direct depolymerization under moderate conditions is often limited by kinetic constrains of individual enzyme. Here, we engineer and optimize modular protein scaffolds that utilize orthogonal interaction domains, including the cohesin-dockerin pairs from bacterial cellulosomes and the SH3 ligand/domain pair from mouse Crk, to assemble complementary hydrolases (PETase, MHETase, and ICCG) into a synergistic multi-enzyme cascade. This architecture overcomes intermediate inhibition, efficiently converting PET hydrolysis products into the final monomers, terephthalic acid (TPA) and ethylene glycol (EG), outperforming previous multi-enzyme systems. The systems application is further evaluated by stability enhancement via immobilization on metal-organic frameworks (MOFs), coupling depolymerization to the valorization of EG into glycolic acid (GA), and adapting the system for scalable whole-cell biocatalysis. This scaffold-based multi-enzyme approach provides a new strategy for developing integrated biocatalytic systems to advance a circular PET economy.

synthetic biology↗

bioRxiv2024

Spatial and Single Cell Mapping of Castleman Disease Reveals Key Stromal Cell Types and Cytokine Pathways

Castleman disease (CD) is inflammatory lymphoproliferative disorder of unclear etiology. To determine the cellular and molecular basis of CD, we analyzed the spatial proteome of 4,485,009 single cells, transcriptome of 50,117 single nuclei, immune repertoire of 8187 single nuclei, and pathogenic mutations in Unicentric CD, idiopathic Multicentric CD, HHV8-associated MCD, and reactive lymph nodes. CD was characterized by increased non-lymphoid and stromal cells that formed unique microenvironments where they interacted with lymphoid cells. Interaction of activated follicular dendritic cell (FDC) cytoplasmic meshworks with mantle zone B cells was associated with B cell activation and differentiation. VEGF, IL-6, MAPK, and extracellular matrix pathways were elevated in stromal cells of CD. CXCL13+ FDCs, PDGFRA+ T-zone reticular cells (TRC), and ACTA2-positive perivascular reticular cells (PRC) were identified as the predominant source of increased VEGF expression and IL-6 signaling in CD. VEGF expression by FDCs was associated with peri-follicular neovascularization. FDC, TRC and PRC of CD activated JAK-STAT, TGF{beta}, and MAPK pathways via ligand-receptor interactions involving collagen, integrins, complement components, and VEGF receptors. T, B and plasma cells were polyclonal but showed class-switched and somatically hypermutated IgG1+ plasma cells consistent with stromal cell-driven germinal center activation. In conclusion, our findings show that stromal cell activation and associated B-cell activation and differentiation, neovascularization and stromal remodeling underlie CD and suggest new targets for treatment. Key pointsO_LICastleman Disease is characterized by activation and proliferation of CXCL13+ FDCs, PDGFRA+ reticular cells, and ACTA2-positive PRCs. C_LIO_LIVEGF and IL-6 from lymph node stromal cells are associated with B-cell activation and differentiation, endothelial proliferation, and inflammation in CD C_LI

pathology↗

bioRxiv2024

Molecular mechanisms of uric acid transport by the native human URAT1 and its inhibition by anti-gout drugs

Gout, a common and painful disease, stems from hyperuricemia, where elevated blood uric acid levels lead to urate crystal formation in joints and kidneys. The human urate transporter 1 (hURAT1) plays a critical role in urate homeostasis by facilitating urate reabsorption in the renal proximal tubule, making it a key target for gout therapy. Pharmacological inhibition of hURAT1 with drugs such as dotinurad, benzbromarone, lesinurad, and verinurad promotes uric acid excretion and alleviates gout symptoms. Here we present cryo-electron microscopy structures of native hURAT1 bound with these anti-gout drugs in the inward-open state, and with uric acid in inward-open, outward-open, and occluded states. Complemented by mutagenesis and cell-based assays, these structures reveal the mechanisms of uric acid reabsorption and hURAT1 inhibition. Our findings elucidate the molecular basis of uric acid transport and anti-gout medication action, and provide a structural framework for the rational design of next-generation therapies for hyperuricemia and gout.

biochemistry↗

bioRxiv2024

EPOP Restricts PRC2.1 Targeting to Chromatin by Directly Modulating Enzyme Complex Dimerization

Polycomb repressive complex 2 (PRC2) mediates developmental gene repression as two classes of holocomplexes, PRC2.1 and PRC2.2. EPOP is an accessory subunit specific to PRC2.1, which also contains PCL proteins. Unlike other accessory subunits that collectively facilitate PRC2 targeting, EPOP was implicated in an enigmatic inhibitory role, together with its interactor Elongin BC. We report an unusual molecular mechanism whereby EPOP regulates PRC2.1 by directly modulating its oligomerization state. EPOP disrupts the PRC2.1 dimer and weakens its chromatin association, likely by disabling the avidity effect conferred by the dimeric complex. Congruently, an EPOP mutant specifically defective in PRC2 binding enhances genome-wide enrichments of MTF2 and H3K27me3 in mouse epiblast-like cells. Elongin BC is largely dispensable for the EPOP-mediated inhibition of PRC2.1. EPOP defines a distinct subclass of PRC2.1, which uniquely maintains an epigenetic program by preventing the over-repression of key gene regulators along the continuum of early differentiation.

molecular biology↗

bioRxiv2024

MaskMol: Knowledge-guided Molecular Image Pre-Training Framework for Activity Cliffs with Pixel Masking

Activity cliffs, which refer to pairs of molecules that are structurally similar but show significant differences in their potency, can lead to model representation collapse and make the model challenging to distinguish them. Our research indicates that as molecular similarity increases, graph-based methods struggle to capture these nuances, whereas imagebased approaches effectively retain the distinctions. Thus, we developed MaskMol, a knowledge-guided molecular image selfsupervised learning framework. MaskMol accurately learns the representation of molecular images by considering multiple levels of molecular knowledge, such as atoms, bonds, and substructures. By utilizing pixel masking tasks, MaskMol extracts fine-grained information from molecular images, overcoming the limitations of existing deep learning models in identifying subtle structural changes. Experimental results demonstrate MaskMols high accuracy and transferability in activity cliff estimation and compound potency prediction across 20 different macromolecular targets, outperforming 25 state-of-the-art deep learning and machine learning approaches. Visualization analyses reveal MaskMols high biological interpretability in identifying activity cliff-relevant molecular substructures. Notably, through MaskMol, we identified candidate EP4 inhibitors that could be used to treat tumors. This study not only raises awareness about activity cliffs but also introduces a novel method for molecular image representation learning and virtual screening, advancing drug discovery and providing new insights into structure-activity relationships (SAR). Code is available at https://github.com/ZhixiangCheng/MaskMol.

bioinformatics↗

bioRxiv2024

Cholinergic signaling differentially regulates song premotor circuits to stabilize songs in songbirds

Cholinergic modulation plays an important role in motor skill performance, including vocal control. In songbirds, song motor nucleus RA simultaneously receives inputs from song nuclei HVC and LMAN, and then its projection neurons (RAPNs) generate song motor control output. Using electrophysiological and pharmacological methods, we found that cholinergic signaling can enhance song stability by reducing HVC-RAPN excitatory synaptic transmission in adult male zebra finches, mediated by mAChRs. Although nAChRs are not effective overall, cholinergic signaling can also decrease LMAN-RAPN excitatory synaptic transmission induced by electrical stimulation via nAChRs, suggesting the potential role of cholinergic regulation in song behavior through LMAN-RA pathway. On the contrary, in adult female zebra finches, only LMAN-RAPN synaptic transmission was reduced by cholinergic signaling via mAChRs. The role of differential cholinergic regulation of song premotor circuits in songbirds singing provides insights into the neural control mechanism of motor skill performance.

neuroscience↗

bioRxiv2024

δ-α cell-to-cell interactions modulate pancreatic islet Ca2+ oscillation modes

Glucose-induced pancreatic islet hormone release is tightly coupled with oscillations in cytoplasmic free Ca2+ concentration of islet cells, which is regulated by a complex interplay between intercellular and intracellular signaling. {delta} cells, which entangle with cells located at the islet periphery, are known to be important paracrine regulators. However, the role of {delta} cells in regulating Ca2+ oscillation pattern remains unclear. Here we show that {delta}- cell-to-cell interactions are the source of variability in glucose-induced Ca2+ oscillation pattern. Somatostatin secreted from {delta} cells prolonged the islets oscillation period in an cell mass-dependent manner. Pharmacological and optogenetic perturbations of {delta}- interactions led islets to switch between fast and slow Ca2+ oscillations. Continuous adjustment of {delta}- coupling strength caused the fast oscillating islets to transition to mixed and slow oscillations. We developed a mathematical model, demonstrating that the fast-mixed-slow oscillation transition is a Hopf bifurcation. Our findings provide a comprehensive understanding of how {delta} cells modulate islet Ca2+ dynamics and reveal the intrinsic heterogeneity of islets due to the structural composition of different cell types. HighlightsO_LISomatostatin slows down islet Ca2+ oscillations in an cell mass-dependent manner. C_LIO_LIPharmacological and optogenetic perturbations of {delta}- interaction cause islet Ca2+ oscillation mode switching. C_LIO_LIContinuous tuning of {delta}- interaction strength induces fast-mixed-slow oscillation transition successively. C_LIO_LIMathematical modeling shows the fast-mixed-slow oscillation transition as a Hopf bifurcation. C_LI

systems biology↗

bioRxiv2024

Sapphire-Based Optrode for Low Noise Neural Recording and Optogenetic Manipulation

Electrophysiological recordings of neurons in deep brain regions using optogenetic stimulation are essential to understanding and regulating the role of complex neural activity in biological behavior and cognitive function. Optogenetic techniques have significantly advanced neuroscience research by enabling the optical manipulation of neural activities. Because of the significance of the technique, constant advancements in implantable optrodes that integrate optical stimulation with low-noise, large-scale electrophysiological recording are in demand to improve the spatiotemporal resolution for various experimental designs and future clinical applications. However, robust and easy-to-use neural optrodes that integrate neural recording arrays with high-intensity light emitting diodes (LEDs) are still lacking. Here, we propose a neural optrode based on Gallium Nitride (GaN) on sapphire technology, which integrates a high-intensity blue LED with a 5x2 recording array monolithically for simultaneous neural recording and optogenetic manipulation. To reduce the noise interference between the recording electrodes and the LED, which is in close physical proximity, three metal grounding interlayers were incorporated within the optrode, and their ability to reduce LED-induced artifacts during neural recording was confirmed through both electromagnetic simulations and experimental demonstrations. The capability of the sapphire optrode to record action potentials has been demonstrated by recording the firing of mitral/tuft cells in the olfactory bulbs of mice in vivo. Additionally, the elevation of action potential firing due to optogenetic stimulation observed using the sapphire probe in medial superior olive (MSO) neurons of the gerbil auditory brainstem confirms the capability of this sapphire optrode to precisely access neural activities in deep brain regions under complex experimental designs.

neuroscience↗

bioRxiv2024

Causal Associations of Circulating Helicobacter pylori Antibodies with 5 Skin Disorders: A Mendelian Randomization Analysis

Helicobacter pylori (H. pylori) infection, a prevalent bacterial ailment affecting the stomach, has been linked to diverse gastrointestinal disorders. Nevertheless, the correlation between H. pylori infection and skin disorders has not been definitively established. We use Mendelian randomization analysis to explore causal relationships with seven pylori antibody levels and five skin diseases, such as rosacea, psoriasis, alopecia areata, pruritus and urticaria. The primary analytical method employed was inverse variance weighted (IVW), and a sensitivity analysis was executed to evaluate the robustness of the primary findings. The results revealed a positive causal relationship between H. pylori catalase antibody levels and AA (IVW: OR = 1.32, 95% CI = 1.07 to 1.61, P = 0.008), as well as a positive causal relationship between H. pylori UreA antibody levels and pruritus (IVW: OR = 1.17, 95% CI = 1.05 to 1.31, P = 0.006). These effects were robust to sensitivity analyses. Our results suggested that H. pylori infection was a risk factor for AA and pruritus. This finding may have implications for the prevention and treatment of these skin disorders.

genomics↗

bioRxiv2024

Discovery of a single-subunit oligosaccharyltransferase that enables glycosylation of full-length IgG antibodies in Escherichia coli

Human immunoglobulin G (IgG) antibodies are one of the most important classes of biotherapeutic agents and undergo glycosylation at the conserved N297 site in the CH2 domain, which is critical for IgG Fc effector functions and anti-inflammatory activity. Hence, technologies for producing authentically glycosylated IgGs are in high demand. While attempts to engineer Escherichia coli for this purpose have been described, they have met limited success due in part to the lack of available oligosaccharyltransferase (OST) enzymes that can install N-linked glycans within the QYNST sequon of the IgG CH2 domain. Here, we identified a previously uncharacterized single-subunit OST (ssOST) from the bacterium Desulfovibrio marinus that exhibited greatly relaxed substrate specificity and, as a result, was able to catalyze glycosylation of native CH2 domains in the context of both a hinge-Fc fragment and a full-length IgG. Although the attached glycans were bacterial in origin, conversion to a homogeneous, asialo complex-type G2 N-glycan at the QYNST sequon of the E. coli-derived hinge-Fc was achieved via chemoenzymatic glycan remodeling. Importantly, the resulting G2-hinge-Fc exhibited strong binding to human Fc{gamma}RIIIa (CD16a), one of the most potent receptors for eliciting antibody-dependent cellular cytotoxicity (ADCC). Taken together, the discovery of a unique ssOST from D. marinus provides previously unavailable biocatalytic capabilities to the bacterial glycoprotein engineering toolbox and opens the door to using E. coli for the production and glycoengineering of human IgGs and fragments derived thereof.

synthetic biology↗