Biology subjects

Ouyang, S.

Publications and source records attributed to Ouyang, S..

4 recordsLinked to original sources

bioRxiv2020

Evidence of the Recombinant Origin and Ongoing Mutations in Severe Acute Respiratory Syndrome 2 (SARS-COV-2)

The recent global outbreak of viral pneumonia designated as Coronavirus Disease 2019 (COVID-19) by coronavirus (SARS-CoV-2) has threatened global public health and urged to investigate its source. Whole genome analysis of SARS-CoV-2 revealed ~96% genomic similarity with bat CoV (RaTG13) and clustered together in phylogenetic tree. Furthermore, RaTGl3 also showed 97.43% spike protein similarity with SARS-CoV-2 suggesting that RaTGl3 is the closest strain. However, RBD and key amino acid residues supposed to be crucial for human-to-human and cross-species transmission are homologues between SARS-CoV-2 and pangolin CoVs. These results from our analysis suggest that SARS-CoV-2 is a recombinant virus of bat and pangolin CoVs. Moreover, this study also reports mutations in coding regions of 125 SARS-CoV-2 genomes signifying its aptitude for evolution. In short, our findings propose that homologous recombination has been occurred between bat and pangolin CoVs that triggered cross-species transmission and emergence of SARS-CoV-2, and, during the ongoing outbreak, SARS-CoV-2 is still evolving for its adaptability.

microbiology↗

bioRxiv2020

Molecular basis of ubiquitination catalyzed by the bacterial transglutaminase MavC

The Legionella pneumophila effector MavC is a transglutaminase that carries out atypical ubiquitination of the ubiquitin (Ub) E2 conjugation enzyme UBE2N by catalyzing the formation of an isopeptide bond between Gln40 of Ub and Lys92 (or to a less extent, Lys94) of UBE2N, which results in inhibition of UBE2N signaling in the NF-{kappa}B pathway. In the absence of UBE2N, MavC deamidates Ub at Gln40 or catalyzes self-ubiquitination. However, the mechanisms underlying these enzymatic activities of MavC are not fully understood at molecular level. In this study, we obtained the structure of the MavC-UBE2N-Ub ternary complex that represents a snapshot of covalent cross-linking of UBE2N and Ub catalyzed by MavC. The structure reveals the unique way by which the cross-linked catalytic product UBE2N-Ub binds mainly to the Insertion and the Tail domains of MavC prior to its release. Based on our structural, biochemical and mutational analyses, we proposed the catalytic mechanism for both the deamidase and the transglutaminase activities of MavC. Finally, by comparing the structures of MavC and MvcA, the homologous protein that reverses MavC-induced UBE2N ubiquitination, we identified several key regions of the two proteins responsible for their opposite enzymatic activity. Our results provide insights into the mechanisms for substrate recognition and ubiquitination mediated by MavC as well as explanations for the opposite activity of MavC and MvcA.

microbiology↗

bioRxiv2020

Cryo-electron microscopy structure of the SADS-CoV spike glycoprotein provides insights into an evolution of unique coronavirus spike proteins

The current outbreak of Coronavirus Disease 2019 (COVID-19) by a novel betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has aroused great public health concern. Coronavirus has a history of causing epidemics in human and animals. In 2017 an outbreak in piglets by a novel coronavirus was emerged designated as swine acute diarrhea syndrome coronavirus (SADS-CoV) which is originated from the same genus of horseshoe bats (Rhinolophus) as Severe Acute Respiratory Syndrome CoV (SARS-CoV) having a broad species tropism. In addition to human cells, it can also infect cell lines from diverse species. Coronavirus host range is determined by its spike glycoprotein (S). Given the importance of S protein in viral entry to cells and host immune responses, here we report the cryo-EM structure of the SADS-CoV S in the prefusion conformation at a resolution of 3.55 [A]. Our study reveals that SADS-CoV S structure takes an intra-subunit quaternary packing mode where the NTD and CTD from the same subunit pack together by facing each other. The comparison of NTD and CTD with that of the other four genera suggests the evolutionary process of the SADS-CoV S. Moreover, SADS-CoV S has several characteristic structural features, such as more compact architecture of S trimer, and masking of epitopes by glycan shielding, which may facilitate viral immune evasion. These data provide new insights into the evolutionary relationships of SADS-CoV S and would extend our understanding of structural and functional diversity, which will facilitate to vaccine development.

microbiology↗

bioRxiv2018

Study of the binding mechanisms between palytoxin and its aptamer by docking and molecular simulation

This paper provides a feasible model for aptamer and its target in molecular structure analysis and interaction mechanism. In this study, modeling and dynamic simulation of ssDNA aptamer (P-18S2) and target (Palytoxin, PTX) were performed separately. Then, the combination mechanism of DNA and PTX were predicted, and docking results showed that PTX can combine steadily in the groove at the top of DNA model trough strong hydrogen-bonds and electrostatic interaction. Therefore, we have further truncated and optimized to P-18S2 by simulating, at the same time, we also confirmed the reliability of simulative results by experimenting. Combining with the experimental and computational results, we provide a more reasonable interpretation for the high affinity and specific binding of P-18S2 and PTX and offer the basis for aptamer development in molecular diagnostics and therapeutic application.\n\nAuthor summaryIn order to further study the complex structure and interaction of P-18S2 and PTX, a series of molecular modeling program were designed, including modeling, traditional dynamics simulation and molecular docking. Modeling results reveal that the structure of P-18S2 is a DNA G-quadruplex. Meanwhile, the 3D structure of PTX with lowest total energy after equilibrium was selected to use for the subsequent simulations. Then, based on the DNA with G-quadruplex structure, the combination model of DNA and PTX were predicted, and docking results showed that PTX can combine steadily in the groove at the top of DNA model trough strong hydrogen-bonds and electrostatic interaction. Futhermore, we compared the affinity of 6 optimized aptamers by computer simulating to primary P-18S2 bind to PTX respectively, the results showed no significant difference. Therefore, we have further truncated and optimized to P-18S2. In addition, this paper further refined research method based on our previous study[17], the instability of the target structure was considered and optimized, and the biological experiments were used to confirm the veracity of the simulative results. Combining with the experimental and computational methods, we obtained a reasonable interpretation for the high affinity and specific binding of P-18S2 and PTX. In summary, we established a feasible model for aptamer and its target in molecular structure analysis and interaction mechanism, and offer the basis for the study of aptamer development in molecular diagnostics and therapeutic application.

molecular biology↗