Viral O-acetylesterases were first identified in several viruses, including influenza C viruses and coronaviruses. These enzymes are capable of removing cellular receptors from the surface of target cells. Hence they are also known as "receptor destroying" enzymes. We have cloned and expressed several recombinant viral O-acetylesterases. These enzymes were secreted from Sf9 insect cells as chimeric proteins fused to eGFP. A purification scheme to isolate the recombinant O-acetylesterase of influenza C virus was developed. The recombinant enzymes derived from influenza C viruses specifically hydrolyze 9-O-acetylated sialic acids, while that of sialodacryoadenitis virus, a rat coronavirus related to mouse hepatitis virus, is specific for 4-O-acetylated sialic acid. The recombinant esterases were shown to specifically de-O-acetylate sialic acids on glycoconjugates. We have also expressed esterase knockout proteins of the influenza C virus hemagglutinin-esterase. The recombinant viral proteins can be used to unambiguously identify O-acetylated acids in a variety of assays.
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http://dx.doi.org/10.1023/B:GLYC.0000043292.64358.f1 | DOI Listing |
Appl Microbiol Biotechnol
January 2025
Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional No, 2508, C.P. 07360, Mexico City, Mexico.
One of the most significant bacteriophage technologies is phage display, in which heterologous peptides are exhibited on the virion surface. This work describes the display of λ decorative protein D linked to the E protein domain III of Zika virus (D-ZE), to the GFP protein (D-GFP), or to different domain III epitopes of the E protein (D-TD), exhibited on the surface of an in vitro evolved lambda phage (λ). This phage harbors a gene D deletion and was subjected to directed evolution using Escherichia coli W3110/pD-ZE as background.
View Article and Find Full Text PDFSci Rep
January 2025
Research & Development, Lonza Houston, Inc., 14905 Kirby Dr, Houston, TX, 77047, USA.
Recombinant adeno-associated virus (rAAV) has emerged as the vector of choice for in vivo gene delivery, with numerous clinical trials underway for the treatment of various human diseases. Utilizing rAAV in gene therapy requires a highly precise quantification method to determine the viral genome titer and further establish the optimal therapeutic dosage for a rAAV product. The conventional single-channel droplet digital PCR (1D ddPCR) method offers only partial information regarding the viral vector genome titer, lacking insights into its integrity.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Junior Research Group Herpesviruses, Infection Biology Unit, German Primate Center-Leibniz Institute for Primate Research, Göttingen, Germany.
Interaction with host cell receptors initiates internalization of Kaposi's sarcoma-associated herpesvirus (KSHV) particles. Fusion of viral and host cell membranes, which is followed by release of the viral capsid into the cytoplasm, is executed by the core fusion machinery composed of glycoproteins H (gH), L (gL), and B (gB), that is common to all herpesviruses. KSHV infection has been shown to be sensitive to inhibitors of vacuolar acidification, suggestive of low pH as a fusion trigger.
View Article and Find Full Text PDFImmunity
January 2025
Garvan Institute of Medical Research, Darlinghurst, NSW, Australia; St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia. Electronic address:
The unexplained association between infection and autoimmune disease is strongest for hepatitis C virus-induced cryoglobulinemic vasculitis (HCV-cryovas). To analyze its origins, we traced the evolution of pathogenic rheumatoid factor (RF) autoantibodies in four HCV-cryovas patients by deep single-cell multi-omic analysis, revealing three sources of B cell somatic mutation converged to drive the accumulation of a large disease-causing clone. A method for quantifying low-affinity binding revealed recurring antibody variable domain combinations created by V(D)J recombination that bound self-immunoglobulin G (IgG) but not viral E2 antigen.
View Article and Find Full Text PDFJ Virol
January 2025
Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
The common cold coronaviruses are a source of ongoing morbidity and mortality particularly among elderly and immunocompromised individuals. While cross-reactive immune responses against multiple coronaviruses have been described following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination, it remains unclear if these confer any degree of cross-protection against the common cold coronaviruses. A recombinant fowl adenovirus vaccine expressing the SARS-CoV-2 spike protein (FAdV-9-S19) was generated, and protection from SARS-CoV-2 challenge was shown in K18-hACE2 mice.
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