Biology subjects

Coulibaly, F.

Publications and source records attributed to Coulibaly, F..

4 recordsLinked to original sources

bioRxiv2025

High-stability, clamp-free soluble Sarbecovirus spike trimers and their potential for pan-Sarbecovirus vaccine development.

Broadly effective vaccines are needed to protect against future pandemics caused by severe acute respiratory syndrome coronavirus (SARS CoV)-like coronaviruses (sarbecoviruses). The development of simple trimeric subunit vaccines based on the Sarbecovirus spike (S) has proven problematic due to the unstable nature of the S trimer. Here we developed clamp-free, highly stable soluble S trimers by truncating the stem helix to maximize yield and covalently linking the 3 monomers via engineered disulfides to increase thermostability. In K18hACE2 mice, covalently linked SARS CoV-2 S trimers elicited >10-fold higher neutralizing antibody (NAb) titres than parental unlinked trimers and protected the mice against viral challenge. A trivalent vaccine formulation comprised of covalently stabilized spikes derived from 3 divergent ACE2-using Sarbecovirus clades elicited broad and potent neutralizing activity in mice. The covalently linked S trimers were stable at 37{degrees}C for 112 days and remained intact following lyophilization and storage at ambient temperature for 6 months. This study establishes a framework for producing simple and stable highly immunogenic pan-Sarbecovirus S subunit vaccines that can be stored and distributed in the absence of a cold chain.

microbiology↗

bioRxiv2024

Convergent evolution of viral-like Borg archaeal extrachromosomal elements and giant eukaryotic viruses

Borgs are huge extrachromosomal elements of anaerobic methane-oxidizing archaea. They exist in exceedingly complex microbiomes, lack cultivated hosts and have few protein functional annotations, precluding their classification as plasmids, viruses or other. Here, we used in silico structure prediction methods to investigate potential roles for [~]10,000 Borg proteins. Prioritizing analysis of multicopy genes that could signal importance for Borg lifestyles, we uncovered highly represented de-ubiquitination-like Zn-metalloproteases that may counter host targeting of Borg proteins for proteolysis. Also prevalent are clusters of multicopy genes for production of diverse glycoconjugates that could contribute to decoration of the host cell surface, or of putative capsid proteins that we predict multimerize into hexagonal arrays. Features including megabase-scale linear genomes with inverted terminal repeats, genomic repertoires for energy metabolism, central carbon compound transformations and translation, and pervasive direct repeat regions are shared with giant viruses of eukaryotes, although analyses suggest that these parallels arose via convergent evolution. If Borgs are giant archaeal viruses they would fill the gap in the tri(um)virate of giant viruses of all three domains of life. One Sentence SummaryProtein analyses, informed by in silico protein structure prediction, revealed that Borgs share numerous features with giant eukaryotic viruses, suggesting that Borgs have a viral-like lifestyle and evolutionary convergence of large extrachromosomal elements across the Domains of Life.

microbiology↗

bioRxiv2024

Mimivirus encodes an essential MC1-like non-histone architectural protein involved in DNA condensation

The first giant virus discovered, Acanthamoeba polyphaga mimivirus (APMV), has a 1.2 Mb dsDNA genome organized as genomic fiber within the capsid. This fiber is comprised of a proteinaceous shell of [~]30 nm diameter that encloses the folded DNA. Surprisingly, for the assembly of the enormous genome of APMV, no DNA condensing protein has been reported to date. Our analysis of the uncharacterized packaged protein complement of Mimivirus led to the identification of a putative DNA-bending archaeal MC1 domain in a hypothetical protein (gp275) coded by the R252 gene. Gene knock-out analysis shows that gp275 is critical for viral multiplication. Biochemical and microscopic characterization further demonstrates the compaction of DNA upon binding to gp275. Together, this study suggests that gp275 is an MC1-like architectural protein involved in the organization of the genomic DNA within the capsid of Mimivirus.

molecular biology↗

bioRxiv2021

The dengue virus NS1 protein conveys pro-inflammatory signals by docking onto human high-density lipoproteins

The nonstructural NS1 protein is a virulence factor secreted by dengue virus (DENV)-infected cells. NS1 is known to alter the complement system, activate immune cells and perturb endothelial barriers. Here we show that pro-inflammatory signals are triggered by a high affinity complex formed between NS1 and human high-density lipoproteins (HDL). Electron microscopy images of the NS1-HDL complexes show spherical HDL particles with rod-shaped NS1 protrusions on their surface. These complexes are readily detectable in the plasma of hospitalized dengue patients using anti-apolipoprotein A-I (ApoA-I) antibodies specific of the HDL moiety. The functional reprogramming of HDL particles by the NS1 protein as a means to exacerbate systemic inflammation during DENV infection provides a new paradigm linking the human lipoprotein network to dengue pathogenesis.

microbiology↗