Biology subjects

Cong, Y.

Publications and source records attributed to Cong, Y..

At least 19 recordsLinked to original sources

bioRxiv2026

Repurposing of the assembly chaperone PAC1-PAC2 defines a specialized proteasome landscape in mature mammalian sperm

Mature mammalian sperm rely on active proteasomes containing the testis-specific subunit 4s for capacitation, acrosomal exocytosis and fertilization, but how these proteasomes are structurally specialized remains unclear. We determine the endogenous proteasome landscape of mature bovine spermatozoa and testis using cryo-electron microscopy. We resolve five sperm proteasome assemblies: PA200-20S, free 20S, a previously unrecognized PA200-20S-PAC1/2 hybrid, and PAC1/2-20S complexes capped at one or both ends. Unexpectedly, the PAC1/2-bound complexes are mature and POMP-free, selectively incorporated for 4s, lack 2, and adopt a PAC1/2 orientation and gate configuration distinct from known assembly intermediates. Together with elevated proteolytic activity, these features indicate that PAC1/2 is repurposed from a transient assembly chaperone into a stable post-assembly regulator in mature sperm. 4s-containing proteasomes assemble through the canonical PAC1-PAC4/POMP pathway yet may follow {beta}2-{beta}3-{beta}1 incorporation ordering; functionally, 4s incorporation remodels the sCP surface and enhances peptidase activities, definining the spermatoproteasomes as a hyperactive 20S variant. PAC1/2-bound proteasomes are absent from testis, where PA200-20S and 26S proteasomes are present, while 26S proteasomes are nearly lost in mature sperm. Our findings define a sperm-specific, ATP-independent proteasome landscape, expand the functional repertoires of 4s and PAC1/2, and provide a structural framework for proteasome specialization in male fertility.

cell biology↗

bioRxiv2026

TRiC folds the giant ciliary protein IFT172 via a non-canonical open-state mechanism

The eukaryotic chaperonin TRiC/CCT is essential for folding complex proteins, yet how it folds substrates that exceed its closed chamber capacity remains a longstanding paradox. Here, we define the folding pathway of IFT172, the largest subunit ([~]200 kDa) of the intraflagellar transport (IFT) machinery, and uncover a "divide-and-conquer" mechanism. TRiC and HSP70 engage IFT172 concurrently but on distinct domains: TRiC captures the N-terminal WD40 {beta}-propellers within its chamber, whereas HSP70 independently stabilizes the C-terminal TPR domain in the cytosol. To accommodate this oversized client, specific TRiC subunits (CCT4, CCT2, and CCT7) undergo pronounced Z-shaped outward bending, thereby expanding the chamber. Unexpectedly, the first WD40 domain reaches a near-folded state within the open, ATP-bound chamber, and subsequent TRiC ring closure triggers substrate ejection rather than encapsulation. This non-canonical "fold-and-eject" mechanism challenges the classical view that the closed chamber is an obligate folding cage. We further demonstrate that this pathway is essential for ciliary functions in vivo, and reveal a conserved mode of chaperonin recognition among IFT components bearing tandem WD40-TPR architectures. Together, our findings establish a new paradigm for the folding of oversized, multi-domain proteins and identify TRiC as a central proteostasis hub in ciliary biogenesis, with direct implications for ciliopathy pathogenesis.

biochemistry↗

bioRxiv2026

Disrupted TRiC allostery and conformational equilibrium by LCA-linked mutations: structural and functional insights

The eukaryotic chaperonin TRiC/CCT is essential for proteostatis, yet the molecular basis of its subunit-specific pathologies remains poorly understood. Here, we elucidate the molecular mechanism of Leber Congenital Amaurosis (LCA), a severe hereditary retinal dystrophy arised from mutations in the CCT2 subunit of TRiC. By integrating cryo-electron microscopy, biochemistry, and proteomics, we demonstrate that LCA-associated mutations (T400P and R516H in CCT2) disrupt TRiCs critical intra-molecular and intra-ring allosteric network and impair its functional cycle, drastically reducing the population of the folding-active closed state. Unexpectedly, we captured a fully folded endogenous -tubulin within the mutant TRiC chamber, revealing a unique CCT8 C-terminal tail involved folding pathway, distinct from {beta}-tubulin. Furthermore, cellular proteomics revealed that TRiC dysfunction causes a specific downregulation of essential SLC membrane transporters. We propose that the loss of these transporters is likely catastrophic for metabolically demanding tissues like the retina and developing embryo. Our work provides a direct mechanistic link between TRiC structural defects and LCA pathology, offering a new framework for understanding etiology of chaperonopathies.

biochemistry↗

bioRxiv2025

Eosinophil-derived COX-2 protects against experimental colitis through the PGE2-IL-22 axis

Inflammatory bowel disease (IBD) is driven by a breakdown in immune regulation and epithelial barrier function, yet the contribution of eosinophils to this process has remained poorly defined and controversial. While eosinophils infiltrate the intestinal mucosa during both flares and remission, their role in shaping disease outcomes is unclear. Our RNA-seq analyses of colonic eosinophils isolated from dextran sulfate sodium (DSS)-treated mice revealed a significant upregulation of cyclooxygenase (Cox)-2 (gene name, Ptgs2). Eosinophil-specific deletion of Cox-2 (Ptgs2fl/fleoCre+/-) reduced IL-22 production and exacerbated DSS- and trinitrobenzene sulfonic acid (TNBS)-induced colitis, characterized by greater weight loss, higher disease activity, colon shortening, and epithelial injury. Administration of recombinant IL-22 reversed these phenotypes. Mechanistically, eosinophil-derived COX-2 enhanced IL-22 production by type 3 Innate lymphoid cells (ILC3s) through prostaglandin E2 (PGE2) signaling. Consistently, Ptgs2fl/fleoCre+/-mice exhibited reduced colonic PGE2 levels, while PGE2 analog treatment restored IL-22 production and mucosal protection. Our findings identify eosinophil-derived COX-2 and PGE2 as a critical regulator of IL-22 production during colitis, uncovering a previously unrecognized eosinophil-ILC3 crosstalk that safeguards the intestinal barrier and represents a promising therapeutic target in IBD. Significance StatementThe role of eosinophils in inflammatory bowel disease (IBD) has remained unresolved. We identify eosinophil-derived COX-2 as the main source of prostaglandin E2 (PGE2) in colitis, which drives IL-22 production by ILC3s to maintain epithelial protection. This discovery defines a protective eosinophil/PGE2/IL-22 circuit and reveals a therapeutic target to strengthen barrier defense in IBD.

immunology↗

bioRxiv2025

Mechanisms of Ub-independent ODC recognition and translocation by the 26S proteasome revealing proteasome's functional adaptability

While most eukaryotic proteins require ubiquitination for proteasomal degradation, a considerable number of substrates undergo ubiquitin-independent degradation. Ornithine decarboxylase (ODC) is a well-known substrate degraded by the 26S proteasome in a ubiquitin-and cofactor-independent manner. However, the underling mechanism of how ODC is recognized and processed without the ubiquitin tag by the 26S proteasome remain unclear. Here, we present eleven cryo-EM structures of the human 26S proteasome in complex with C-terminal truncated or full-length ODC, capturing the entire degradation process from initial recognition to final unfolding. These structures reveal a dynamic, multivalent recognition process involving sequential engagement with vWA domain of Rpn10, Rpt4/5s coiled-coil, and Rpn2s PC domain, collectively bypassing the need for ubiquitin. Although the folded ODC core is sufficient for initial binding, its flexible C-terminal tail is crucial for allosterically activating the proteasomes AAA+ ATPase motor. Furthermore, we also identify a unique translocation gateway where Rpn11s JAMM motif guides the ODC C-tail into the AAA+ATPase ring, repurposing this deubiquitinase for a novel function. Once activated, the proteasome translocates ODC C-tail and unfolds ODC using its canonical ATP-driven machinery. The continuous structural series from initial substrate recognition through final unfolding elucidates the complete molecular mechanism of ubiquitin-independent ODC degradation.

biophysics↗

bioRxiv2025

LRP8 is a Receptor for Yellow Fever Virus

Yellow fever virus (YFV), an arbovirus causing substantial human morbidity and mortality, was the first human virus discovered over a century ago. The live-attenuated 17D vaccine is among the most successful vaccines in medicine. Despite the importance of YFV, its receptor has remained unknown. Here, we performed a barcoded, genome-wide human ORF library screen and identified LRP8 (also named APOER2) as a receptor for YFV. We show that LRP8 expression specifically boosts YFV infection in cell lines by promoting entry. AAV-mediated expression of human LRP8 in mouse liver aggravates infection and pathology. LRP8 knockdown abolishes YFV infection in brain cells, primary human hepatocytes, and notably in mosquitoes. Biochemically, LRP8 directly interacts with YFV particles via the viral envelope protein. This function of LRP8 is conserved across species, particularly in mosquitoes and primates. A soluble LRP8 decoy protein can block YFV infection in vitro and in mice, providing a potential therapeutic or prophylactic strategy. Our findings provide groundwork for understanding YFV entry, tropism, and pathogenesis, and may enable development of novel therapeutics to treat YFV infection.

microbiology↗

bioRxiv2025

TRiC-assisted folding of class I HDAC family proteins regulated by distinct co-chaperone and cofactor networks

Class I histone deacetylases (HDACs), including HDAC1, HDAC2, HDAC3, and HDAC8, are essential for diverse cellular processes. Although the chaperonin TRiC is implicated in the activation of class I HDACs, the underlying mechanisms remain elusive. Using cryo-electron microscopy (cryo-EM), cross-linking mass spectrometry (XL-MS), and biochemistry analyses, we established class I HDACs as novel TRiC substrates and elucidate TRiC-assisted folding of HDAC1 and HDAC3 during its ATPase cycle, orchestrated by distinct co-chaperone and cofactor networks. In the closed TRiC chamber, both HDAC1 and HDAC3 adopt near-native states with shared binding interfaces. However, their open-state configurations diverge: Hsp70 and PDCD5 engage atop and within TRiC, respectively, for HDAC3, whereas prefoldin (PFD) binds atop TRiC for HDAC1, suggesting roles in substrate delivery and folding modulation. Furthermore, an unexpected bent conformation of CCT4, detected in TRiC-HDAC1 complex, may facilitate co-chaperone dissociation from TRiC. In contrast, HDAC8 folds independently of TRiC. Our study reveals the mechanism governing TRiC-assisted folding of class I HDACs in orchestration of dynamic co-chaperone/cofactor network, shielding new lights on the sophisticated regulatory landscape of TRiC, and open promising avenues for designing peptides or small molecules to selectively modulate TRiC-assisted folding of class I HDACs and other substrates.

molecular biology↗

bioRxiv2025

Themis dominates T cell exhaustion by regulation of TCR and PD-1 signaling

T cell exhaustion is important to protect the host from immunopathology during chronic viral infection, but it also impairs T cell anti-tumor immunity1-5. A fundamental unresolved question is whether and how T cell exhaustion is determined at the onset of TCR signaling6-8. Here we report an unexpected role of Themis, a TCR-proximal signaling molecule9, in T cell exhaustion. Chronic viral infection in mice usually leads to T cell exhaustion and survival of the host. Surprisingly, Themis T-cell conditional knockout mice died from severe CD8+-dependent lung immunopathology in chronic viral infection, showing Themis importance in establishing T cell exhaustion. We found that Themis-deficient CD8+ T cells were hyperactivated at the single-cell level - producing more TNF and IFN{gamma} compared to wild-type counterparts - but defective in population-level expansion. Moreover, TCF-1 and TOX expression were inhibited in Themis-deficient CD8+ T cells, thereby impairing differentiation of exhausted T cell precursors (T-pex) and maintenance of terminally exhausted T cells (T-ex), respectively. Mechanistically, Themis initially promotes TCR signaling to induce PD-1 expression and subsequently mediates PD-1 signaling. In the latter, Themis binds to PD-1 and promotes PD-1 phosphorylation and its recruitment of SHP2, thereby acting as a negative regulator to inhibit T cell effector functions. Without Themis, the orderly regulation of TCR and PD-1 signaling, and therefore exhaustion, is disrupted. Thus, our results unequivocally demonstrate that Themis-mediated early TCR signaling plays a decisive role in T cell exhaustion and provide a novel mechanism of PD-1 signaling through Themis.

immunology↗

bioRxiv2024

Chaperonin TRiC bridges radial spokes for folding proteins locally translated in mammalian sperm flagella

As animals evolved from external to internal fertilization, sperm flagella, which once transiently propelled sperm in water to reach nearby eggs, developed to beat for days or even longer within the female reproductive tract. How flagella were remodeled accordingly remains unclear. Unlike externally fertilizing zebrafish and sea urchin, mammalian sperm flagella feature a unique barrel-shaped bridge between axonemal radial spokes RS1 and RS2, though its components and function remain unknown. Here, using cryo-EM and cryo-ET combined with mass spectrometry and immunofluorescence staining, we reveal that this RS1-RS2 barrel (RRB) in mammalian sperm flagella is a group II chaperonin TRiC/CCT. We purified and resolved the unforeseen cryo-EM structure of TRiC from bovine sperm flagella, discovering that flagella TRiC contains the testis-specific CCT6B subunit. Additionally, we resolved the cryo-ET map of mouse sperm flagella RSs, containing the RRB, achieving unprecedented local resolution of 10-14 [A]. The in-situ RRB map displays two extra densities within its chambers in a polarized manner, suggesting the presence of folding substrates and a co-chaperone (likely phosducin-like 2). Notably, mammalian flagella also contain components of translation machineries and actively synthesize proteins. Our results suggest that the RRB TRiC folds locally translated proteins to sustain mammalian flagella, providing new insights into flagellar remodeling in internally fertilizing species. Our findings also shed lights on male fertility and potential treatments for infertility.

biophysics↗

bioRxiv2024

Antigenic cartography using hamster sera identifies SARS-CoV-2 JN.1 evasion seen in human XBB.1.5 booster sera

Antigenic assessments of SARS-CoV-2 variants inform decisions to update COVID-19 vaccines. Primary infection sera are often used for assessments, but such sera are rare due to population immunity from SARS-CoV-2 infections and COVID-19 vaccinations. Here, we show that neutralization titers and breadth of matched human and hamster pre-Omicron variant primary infection sera correlate well and generate similar antigenic maps. The hamster antigenic map shows modest antigenic drift among XBB sub-lineage variants, with JN.1 and BA.4/BA.5 variants within the XBB cluster, but with five to six-fold antigenic differences between these variants and XBB.1.5. Compared to sera following only ancestral or bivalent COVID-19 vaccinations, or with post-vaccination infections, XBB.1.5 booster sera had the broadest neutralization against XBB sub-lineage variants, although a five-fold titer difference was still observed between JN.1 and XBB.1.5 variants. These findings suggest that antibody coverage of antigenically divergent JN.1 could be improved with a matched vaccine antigen.

microbiology↗

bioRxiv2024

Development of immobilized antibody-based affinity grid strategy and application in on-grid purification of target proteins for high-resolution cryo-EM

In cryo-electron microscopy (cryo-EM), sample preparation, especially for rare or fragile macromolecular assemblies and those suffering from air-water interface denaturation and particle orientation distribution problems, is a major bottleneck. Here, we developed and characterized an immobilized antibody-based affinity grid (IAAG) strategy based on the high-affinity PA tag/NZ-1 antibody epitope tag system. We used Pyr-NHS as a linker to immobilize NZ-1 Fab on the graphene oxide or carbon covered grid surface. We showed that the IAAG grid can enrich the PA-tagged target proteins, and overcome preferred orientation problems. Furthermore, we demonstrated that our IAAG strategy can be utilized for on-grid purification of low-abundance target complexes from cell lysates and enables atomic resolution cryo-EM. This approach greatly streamlines the purification process, reduces the need for large quantities of biological samples, and addresses common challenges encountered in cryo-EM sample preparation. Collectively, our IAAG strategy provides an efficient and robust means for combined sample purification and vitrification feasible for high-resolution cryo-EM. This approach also has the potential for broader applicability in cryo-EM and cryo-ET.

molecular biology↗

bioRxiv2023

DARDN: Identifying transcription factor binding motifs from long DNA sequences using multi-CNNs and DeepLIFT

Characterization of gene regulatory mechanisms in cancer is a key task in cancer genomics. CCCTC-binding factor (CTCF), a DNA binding protein, exhibits specific binding patterns in the genome of cancer cells and has a non-canonical function to facilitate oncogenic transcription programs by cooperating with transcription factors bound at flanking distal regions. Identification of DNA sequence features from a broad genomic region that distinguish cancer-specific CTCF binding sites from regular CTCF binding sites can help find oncogenic transcription factors in a cancer type. However, the long DNA sequences without localization information makes it difficult to perform conventional motif analysis. Here we present DNAResDualNet (DARDN), a computational method that utilizes convolutional neural networks (CNNs) for predicting cancer-specific CTCF binding sites from long DNA sequences and employs DeepLIFT, a method for interpretability of deep learning models that explains the models output in terms of the contributions of its input features [1], for identifying DNA sequence features associated with cancer-specific CTCF binding. Evaluation on DNA sequences associated with CTCF binding sites in T-cell acute lymphoblastic leukemia (T-ALL) and other cancer types demonstrates DARDNs ability in classifying DNA sequences surrounding cancer-specific CTCF binding from control constitutive CTCF binding and identifying sequence motifs for transcription factors potentially active in each specific cancer type. We identified potential oncogenic transcription factors in T-ALL, acute myeloid leukemia (AML), breast cancer (BRCA), colorectal cancer (CRC), lung adenocarcinoma (LUAD), and prostate cancer (PRAD). Our work demonstrates the power of advanced machine learning and feature discovery approach in finding biologically meaningful information from complex high-throughput sequencing data.

bioinformatics↗

bioRxiv2023

High-resolution structure of mouse radial spoke and its in-situ structure in ependymal cilia revealed by cryo-EM and cryo-ET

Radial spokes (RS) transmit mechanochemical signals between the central pair (CP) and axonemal dynein arms to coordinate ciliary motility. However, the high-resolution structure of mammalian RS remains missing. Here, we present the high-resolution cryo-EM structure of mouse RS head-neck complex in both monomer and dimer forms and reveal the intrinsic dynamics of the dimer. We also map the genetic mutations related to primary ciliary dyskinesia and asthenospermia on the head-neck complex. Moreover, we present the unprecedented cryo-ET and sub-tomogram averaging map of mouse ependymal cilia, whose beating creates unidirectional cerebrospinal fluid flow, and build the models for RS1-3, IDAs, and N-DRC. Strikingly, our cryo-ET map reveals the lack of IDA-b/c/e and the absence of tektin filaments within the A-tubule of doublet microtubules in ependymal cilia compared with mammalian respiratory cilia and sperm flagella. This tissue-specific feature may represent an evolutionary choice driven by the functional requirements on ependymal cilia. Our findings reveal the RS head-neck assembly mechanism, shed light on the coordinated rigid and elastic RS-CP interaction modes beneficial for the regulation of asymmetric ciliary beating, and also facilitate understandings on the etiology of ciliary dyskinesia-related ciliopathies.

biophysics↗

bioRxiv2023

Cryo-EM of α-tubulin isotype containing microtubules revealed a contracted structure of α4A/β2A microtubules

Microtubules are hollow /{beta}-tubulin heterodimeric polymers playing critical roles in cells. In vertebrates, both - and {beta}-tubulin have multiple isotypes encoded by different genes, which are intrinsic factors in regulating microtubule functions. However, structures of microtubules composed of different tubulin isotypes, especially -tubulin isotypes, remain largely unknown. Here, we purified recombinant tubulin heterodimers composed of different mouse -tubulin isotypes, including 1A, 1C and 4A, with {beta}-tubulin isotype {beta}2A. We further assembled and determined the cryo-electron microscopy (cryo-EM) structures of 1A/{beta}2A, 1C/{beta}2A, and 4A/{beta}2A microtubules. Our structural analysis demonstrated that 4A/{beta}2A microtubules exhibit a longitudinal contraction between tubulin interdimers compared with 1A/{beta}2A and 1C/{beta}2A microtubules. Collectively, our findings reveal that -tubulin isotype composition could tune microtubule structures, and also provide evidence for the "tubulin code" hypothesis.

biophysics↗

bioRxiv2022

Pathway and mechanism of tubulin folding mediated by TRiC/CCT conjugated with its ATPase cycle revealed by cryo-EM

The eukaryotic chaperonin TRiC/CCT assists the folding of about 10% of cytosolic proteins through an ATP-driven conformational cycle, and the essential cytoskeleton protein tubulin is the obligate substrate of TRiC. Here, we present an ensemble of cryo-EM structures of human TRiC throughout its ATPase cycle, with three of them revealing endogenously engaged tubulin in different folding stages. Our structural and XL-MS analyses suggested a gradual upward translocation and stabilization of tubulin within the TRiC chamber accompanying TRiC ring closure. Remarkably, in the closed TRiC-tubulin-S3 map resolved to 3.1-[A]-resolution, we captured a near-natively folded tubulin. We found the near-natively folded tubulin engaging through its N and C domains mainly with the A and I domains of the CCT3/6/8 subunits through electrostatic and hydrophilic interactions, while the tubulin I domain was found to remain dynamic. Moreover, we also showed the potential role of TRiC C-terminal tails in substrate stabilization and folding. Our study delineates the pathway and molecular mechanism of TRiC-mediated tubulin folding conjugated with TRiC ATPase cycle, and may also inform the design of therapeutic agents targeting TRiC-tubulin interactions.

biochemistry↗

bioRxiv2022

Structural basis of plp2-mediated cytoskeletal protein folding by TRiC/CCT

The eukaryotic chaperonin TRiC/CCT assists the folding of ~10% cytosolic proteins. The essential cytoskeletal proteins tubulin and actin are the obligate substrates of TRiC and their folding involves cochaperone and co-factors. Here, through cryo-EM analysis, we present a more complete picture of yeast TRiC-assisted tubulin and actin folding in the ATPase-cycle, under the coordination of cochaperone plp2. Our structures revealed that in the open C1 and C2 states, plp2 and substrates tubulin/actin engage with TRiC inside its chamber, one per ring. Noteworthy, we captured a ternary TRiC-plp2-tubulin complex in the closed C3 state, engaged with a full-length {beta}-tubulin in the native folded state even loaded with a GTP, and with a plp2 occupying the opposite ring, not reported before. Another closed C4 state revealed an actin in the intermediate state of folding and a plp2 occupying the other ring. Intriguingly, along with TRiC ring closure, we captured a large translocation of plp2 within TRiC chamber coordinating substrate translocation on the CCT6 hemisphere, potentially facilitating substrate stabilization and folding. Our findings provide structural insights into the folding mechanism of the major cytoskeletal proteins tubulin/actin under the coordination of the complex biogenesis machinery TRiC and plp2, and could extend our understanding on the links between cytoskeletal proteostasis and related human diseases.

biophysics↗

bioRxiv2022

Broadly neutralizing antibodies target the coronavirus fusion peptide

The potential for future coronavirus outbreaks highlights the need to develop strategies and tools to broadly target this group of pathogens. Here, using an epitope-agnostic approach, we identified six monoclonal antibodies that bound to spike proteins from all seven human-infecting coronaviruses. Epitope mapping revealed that all six antibodies target the conserved fusion peptide region adjacent to the S2 cleavage site. Two antibodies, COV44-62 and COV44-79, broadly neutralize a range of alpha and beta coronaviruses, including SARS-CoV-2 Omicron subvariants BA.1 and BA.2, albeit with lower potency than RBD-specific antibodies. In crystal structures of Fabs COV44-62 and COV44-79 with the SARS-CoV-2 fusion peptide, the fusion peptide epitope adopts a helical structure and includes the arginine at the S2 cleavage site. Importantly, COV44-79 limited disease caused by SARS-CoV-2 in a Syrian hamster model. These findings identify the fusion peptide as the target of the broadest neutralizing antibodies in an epitope-agnostic screen, highlighting this site as a candidate for next-generation coronavirus vaccine development. One-Sentence SummaryRare monoclonal antibodies from COVID-19 convalescent individuals broadly neutralize coronaviruses by targeting the fusion peptide.

immunology↗

bioRxiv2022

Molecular basis of SARS-CoV-2 Omicron variant receptor engagement and antibody evasion and neutralization

The SARS-CoV-2 Omicron variant exhibits striking immune evasion and is spreading globally at an unprecedented speed. Understanding the underlying structural basis of the high transmissibility and greatly enhanced immune evasion of Omicron is of high importance. Here through cryo-EM analysis, we present both the closed and open states of the Omicron spike, which appear more compact than the counterparts of the G614 strain, potentially related to the Omicron substitution induced enhanced protomer-protomer and S1-S2 interactions. The closed state showing dominant population may indicate a conformational masking mechanism of immune evasion for Omicron spike. Moreover, we capture two states for the Omicron S/ACE2 complex with S binding one or two ACE2s, revealing that the substitutions on the Omicron RBM result in new salt bridges/H-bonds and more favorable electrostatic surface properties, together strengthened interaction with ACE2, in line with the higher ACE2 affinity of the Omicron relative to the G614 strain. Furthermore, we determine cryo-EM structures of the Omicron S/S3H3 Fab, an antibody able to cross-neutralize major variants of concern including Omicron, elucidating the structural basis for S3H3-mediated broad-spectrum neutralization. Our findings shed new lights on the high transmissibility and immune evasion of the Omicron variant and may also inform design of broadly effective vaccines against emerging variants.

biochemistry↗