Bich Ngoc Tran
Email Address
dbstrbn@nus.edu.sg
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Publication Singapore Grouper Iridovirus ORF75R is a Scaffold Protein Essential for Viral Assembly(Nature Publishing Group, 2015) Wang F.; Liu Y.; Zhu Y.; Ngoc Tran B.; Wu J.; Leong Hew C.; BIOLOGY; MECHANOBIOLOGY INSTITUTE; BIOLOGICAL SCIENCESSingapore Grouper Iridovirus (SGIV) is a member of nucleo cytoplasmic large DNA viruses (NCLDV). This paper reports the functional analysis of ORF75R, a major structural protein of SGIV. Immuno fluorescence studies showed that the protein was accumulated in the viral assembly site. Immunogold-labelling indicated that it was localized between the viral capsid shell and DNA core. Knockdown of ORF75R by morpholinos resulted in the reduction of coreshell thickness, the failure of DNA encapsidation, and the low yield of infectious particles. Comparative proteomics further identified the structural proteins affected by ORF75R knockdown. Two-dimensional gel electrophoresis combined with proteomics demonstrated that ORF75R was phosphorylated at multiple sites in SGIV-infected cell lysate and virions, but the vast majority of ORF75R in virions was the dephosphorylated isoform. A kinase assay showed that ORF75R could be phosphorylated in vitro by the SGIV structural protein ORF39L. Addition of ATP and Mg2+ into purified virions prompted extensive phosphorylation of structural proteins and release of ORF75R from virions. These data suggest that ORF75R is a novel scaffold protein important for viral assembly and DNA encapsidation, but its phosphorylation facilitates virion disassembly. Compared to proteins from other viruses, we found that ORF75R shares common features with herpes simplex virus VP22.Publication Biochemical and structural characterization of a recombinant fibrinogen-related lectin from Penaeus monodon(Nature Research, 2021-02-03) Singrang, Nongnuch; Laophetsakunchai, Sirasit; Bich Ngoc Tran; Matsudaira, Paul T.; Tassanakajon, Anchalee; Wangkanont, Kittikhun; BIOLOGICAL SCIENCESFibrinogen-related lectins are carbohydrate-binding proteins of the innate immune system that recognize glycan structures on microbial surfaces. These innate immune lectins are crucial for invertebrates as they do not rely on adaptive immunity for pathogen clearance. Here, we characterize a recombinant fibrinogen-related lectin PmFREP from the black tiger shrimp Penaeus monodon expressed in the Trichoplusia ni insect cell. Electron microscopy and cross-linking experiments revealed that PmFREP is a disulfide-linked dimer of pentamers distinct from other fibrinogen-related lectins. The full-length protein binds N-acetyl sugars in a Ca2+ ion-independent manner. PmFREP recognized and agglutinated Pseudomonas aeruginosa. Weak binding was detected with other bacteria, including Vibrio parahaemolyticus, but no agglutination activity was observed. The biologically active PmFREP will not only be a crucial tool to elucidate the innate immune signaling in P. monodon and other economically important species, but will also aid in detection and prevention of shrimp bacterial infectious diseases. © 2021, The Author(s).Publication Magnetically recyclable CuFe2O4 catalyst for efficient synthesis of bis(indolyl)methanes using indoles and alcohols under mild condition(Elsevier B.V., 2021-01-01) Ngoc-Khanh Nguyen; Minh-Tuan Ha; Hoang Yen Bui; Quang Thang Trinh; Bich Ngoc Tran; Van Tuyen Nguyen; Tran Quang Hung; Tuan Thanh Dang; Xuan Hoan Vu; BIOLOGICAL SCIENCESBis(3-indolyl)methanes (BIM) are highly valuable and appear in the core structure of many natural products and pharmacologically active compounds (anticancer, anti-inflammatory, antiobesity, antimetastatic, antimicrobial, etc.). Herein, we have disclosed an air stable and highly efficient CuFe2O4 heterogeneous catalyst for alkylation of indoles with alcohols to give bis(3-indolyl)methanes in very good yields. The CuFe2O4 catalyst has been found to be magnetically recycled at least five times without losing significant catalytic activity. © 2020Publication Visualization of Assembly Intermediates and Budding Vacuoles of Singapore Grouper Iridovirus in Grouper Embryonic Cells(2016) Liu Y.; Tran B.N.; Wang F.; Ounjai P.; Wu J.; Hew C.L.; BIOLOGICAL SCIENCESIridovirid infection is associated with the catastrophic loss in aquaculture industry and the population decline of wild amphibians and reptiles, but none of the iridovirid life cycles have been well explored. Here, we report the detailed visualization of the life cycle of Singapore grouper iridovirus (SGIV) in grouper cells by cryo-electron microscopy (cryoEM) and tomography (ET). EM imaging revealed that SGIV viral particles have an outer capsid layer, and the interaction of this layer with cellular plasma membrane initiates viral entry. Subsequent viral replication leads to formation of a viral assembly site (VAS), where membranous structures emerge as precursors to recruit capsid proteins to form an intermediate, double-shell, crescent-shaped structure, which curves to form icosahedral capsids. Knockdown of the major capsid protein eliminates the formation of viral capsids. As capsid formation progresses, electron-dense materials known to be involved in DNA encapsidation accumulate within the capsid until it is fully occupied. Besides the well-known budding mechanism through the cell periphery, we demonstrate a novel budding process in which viral particles bud into a tubular-like structure within vacuoles. This budding process may denote a new strategy used by SGIV to disseminate viral particles into neighbor cells while evading host immune response.