Biology subjects

Briers, Y.

Publications and source records attributed to Briers, Y..

13 recordsLinked to original sources

bioRxiv2025

PhaLP 2.0: extending the community-oriented phage lysin database with a SUBLYME pipeline for metagenomic discovery

As biology becomes increasingly data-driven, so too does the field of phage lysins, enzymes that degrade bacterial cell walls and hold promise as alternatives to traditional antibiotics. Five years ago, we introduced PhaLP, a centralized resource for Phage Lytic Protein sequences and associated metadata to support global research efforts. Here, we present PhaLP 2.0, a significantly enhanced database designed to overcome key challenges in the computational study of lysins by integrating newly identified lysins obtained from thousands of metagenomes. To expand the known diversity of lysins beyond those from cultured phages, we developed SUBLYME, a protein embedding-based machine learning Software designed to Uncover and classify Bacteriophage Lysins in Metagenomic datasets. Using embeddings derived from the prior well-curated protein sequences of the original PhaLP database, we trained support vector machines to distinguish lysins from non-lysins in viromes and classify them as either endolysins or virion-associated lysins. The models achieved an average F1-score of 98% on held-out lysin clusters. SUBLYME enabled the discovery of 743,000 new lysin sequences from EnVhogDB, a virome-derived protein database, increasing the number of known lysin clusters by a factor of 40, from 1,000 to 40,000. PhaLP 2.0 entries were annotated by integrating Pfam functional predictions to the refined delineations obtained with SPAED, an algorithm that leverages the predicted aligned error matrix from AlphaFold predictions to identify domain boundaries. Both SUBLYME and the PhaLP 2.0 database are accessible online at https://github.com/Rousseau-Team/sublyme and http://phalp.ugent.be, respectively. Together, these advances establish PhaLP 2.0 as a comprehensive and scalable portal for the discovery, classification, and sequence analysis of phage lysins, paving the way for future antibacterial applications and evolutionary insights. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=59 SRC="FIGDIR/small/692814v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@181e26borg.highwire.dtl.DTLVardef@37e099org.highwire.dtl.DTLVardef@7a7fccorg.highwire.dtl.DTLVardef@5c42f1_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2025

A funnel-type pipeline for accelerating discovery of tailored designer xylanosomes for efficient arabinoxylan valorization

Designer cellulosomes (DCs) are synthetic multi-enzyme complexes composed of a scaffold and docked enzymes, engineered for efficient lignocellulose degradation. However, designing these systems is challenged by an expansive design space, low protein yields, instability, and aggregation. To overcome these significant hurdles, we developed a novel, funnel-type methodological pipeline for the parallel construction, production, and analysis of designer xylanosomes (DXs), a subset of DCs targeting hemicelluloses xylan fraction. This streamlined approach leverages VersaTile, a combinatorial DNA assembly technique, to generate an unprecedented number of modular proteins. We demonstrate the efficient construction of 96 bicatalytic dockerin-enzyme (DE) fusions. Parallel high-throughput assays, including Enzyme-Linked ImmunoSorbent Assay (ELISA) and DNA Sequencer-Assisted Fluorophore-Assisted Carbohydrate Electrophoresis (DSA-FACE), enabled rapid analysis of DE binding efficiencies and substrate preferences, facilitating selection of optimal components for downstream processing. Subsequently, we assembled 23 unique DXs and systematically evaluated their assembly capacity and hydrolytic efficiency. Our findings reveal that DX hydrolytic efficiencies are highly dependent on composition and architecture, yielding either specific arabinoxylan-oligosaccharide (AXOS) mixtures or more complete degradation to monomers. This diversity allows for tailored outcomes, leading to the identification of three superior DX variants. This innovative pipeline significantly accelerates the discovery and optimization of highly efficient multi-enzyme complexes, paving the way for more effective biomass valorization processes. HighlightsO_LIFunnel-type pipeline enables high-throughput testing of designer xylanosomes C_LIO_LIVersaTile allows rapid assembly of an infinite number of bicatalytic dockerin-enzymes C_LIO_LIHigh-throughput assessment of substrate preferences resulting in product profiles C_LIO_LIStreamlined selection yields 23 unique DXs with diverse hydrolytic profiles C_LIO_LIProposed pipeline accelerates discovery of efficient enzyme complexes C_LI

synthetic biology↗

bioRxiv2025

DepoCatalog: Mapping the Diversity of 105 Recombinant Klebsiella Phage Depolymerases Across Sequence, Structure, and Substrate Specificity

A validated catalog of 105 recombinant depolymerases from Klebsiella phages covers 58 KL-types. 46 novel enzymes from prophages, jumbo phages, and common phages are linked to any known enzymatic activity against 14 classical serotypes and 12 genome-defined KL-types. Using activity-based profiling, structure prediction, and domain dissection, we developed a function-guided classification and a five-class structural catalog. This framework reveals highly specific enzymes active against up to three capsule types. K47 CPS was degraded by three diverse protein groups. Structurally similar depolymerases degrading particular CPS were found in distinct phage taxa, with highly conserved enzymes in Drulisvirus specific to K1-, K2-types. The exclusive depolymerases were found in siphoviruses targeting K2 and K62 serotypes. A case study of five structurally similar enzymes degrading KL22/KL37/KL111 and KL25/KL119 capsules suggested specificity switching via amino acid changes or C-domain modification. Klebsiella phage depolymerases catalog sheds light on their diversity, evolution, and potential application.

microbiology↗

bioRxiv2025

SPAED: Harnessing AlphaFold Output for Accurate Segmentation of Phage Endolysin Domains

SummarySPAED is an accessible tool for the accurate segmentation of protein domains that applies hierarchical clustering to the predicted aligned error (PAE) matrix obtained from AlphaFold predictions. It leverages information contained in the PAE matrix to better identify domain-linker boundaries and detect disordered regions. On a dataset of 376 bacteriophage endolysins (proteins that degrade the bacterial cell wall), SPAED achieves a mean intersect-over-union score of 96% and a domain-boundary-distance score of 89% compared to 94% and 70%, respectively, for the state-of-the-art tool Chainsaw. Availability and ImplementationSPAED is available on the web at http://spaed.ca and available for download at https://github.com/Rousseau-Team/spaed. ContactElsa Rousseau - elsa.rousseau@ift.ulaval.ca, Roberto Vazquez - rvazqf@gmail.com

bioinformatics↗

bioRxiv2025

Diversity, structure-function relationships and evolution of cell wall-binding domains of staphylococcal phage endolysins

Endolysins, encoded by phages, lyse bacterial hosts at the end of the replication cycle by degrading peptidoglycan. Consequently, they have evolved in response to host cell wall structures, leading to complex modular architectures, particularly in Gram-positive bacteria. These architectures feature diverse enzymatically active domains (EADs) and cell wall-binding domains (CBDs). This study investigates the structure-function relationships of CBDs in staphylococcal phage endolysins, exploring their evolutionary origins and the extent to which binding specificity can be predicted from sequence data. A set of 182 staphylococcal endolysin sequences was analyzed, revealing predominantly three-domain architectures, occasionally disrupted by species-specific mobile genetic elements. Most CBDs exhibited an SH3-like fold, classified into two major subfamilies: SH3b_P (including the well-characterized SH3_5 family) and SH3b_T. The composition of endolysin domains correlated with specific CBD families, suggesting co-evolution of CBDs and compatible EADs to ensure functional synergy. To assess binding properties, 24 CBDs were fused to eGFP and tested against a panel of staphylococci, revealing diverse specificity profiles. However, no clear correlation emerged between binding specificity, phylogenetic subgroups, or bacterial hosts. This suggests that minor structural modifications significantly impact function and that CBD specificity is not a major selective pressure in the staphylococcal bacteria-phage interface.

molecular biology↗

bioRxiv2024

KlebPhaCol: A community-driven resource for Klebsiella research identified a novel gut phage order associated with the human gut

The growing threat of multidrug-resistant Klebsiella pneumoniae, coupled with its role in gut colonisation, has intensified the search for new treatments, including bacteriophage therapy. Despite increasing documentation of Klebsiella-targeting phages, clinical applications remain limited, with key phage-bacteria interactions still poorly understood. A major obstacle is fragmented access to well-characterised phage-bacteria pairings, restricting the collective advancement of therapeutic and mechanistic insights. To address this gap, we created the Klebsiella Phage Collection (KlebPhaCol), an open-source resource comprising 53 phages and 74 Klebsiella isolates, all fully characterised. These phages span five families - including a novel order, Felixvirales, associated with the human gut - and target 27 sequence types (including ST258, ST11, ST14) and 28 capsular-locus types (including KL1 and KL2), across six Klebsiella species. Freely accessible at www.klebphacol.org, KlebPhaCol invites the scientific community to both use and contribute to this resource, fostering collaborative research and a deeper understanding of Klebsiella-phage interactions beyond therapeutic use.

microbiology↗

bioRxiv2024

A VersaTile approach to reprogram the specificity of the R2-type tailocin towards different serotypes of Escherichia coli and Klebsiella pneumoniae

Phage tail-like bacteriocins, or tailocins, provide a competitive advantage to producer cells by killing closely related bacteria. Morphologically similar to headless phages, their narrow target specificity is determined by receptor-binding proteins (RBPs). While RBP engineering has been used to alter the host range of a selected R2 tailocin from Pseudomonas aeruginosa, the process is labor-intensive, limiting broader application. We introduce a VersaTile-driven R2 tailocin engineering platform to scale up RBP grafting. This platform achieved three key milestones: (1) engineering R2 tailocins specific to Escherichia coli serogroups O26, O103, O104, O111, O145, O146 and O157; (2) reprogramming R2 tailocins to target for the first time capsule and a new species, specifically the capsular serotype K1 of E. coli and K11 and K63 of Klebsiella pneumoniae; (3) creating the first bivalent tailocin with a branched RBP and cross-species activity, effective against both E. coli K1 and K. pneumoniae K11. Over 90% of engineered tailocins were effective, with clear pathways for further optimization identified. ImportanceWhile tailocin engineering is a proven and promising concept, the current engineering approach lacks scalability, limiting a vast exploration. This study advances tailocin engineering by increasing its throughput. Implementing a scaled up approach, we have shown the flexibility of the R2 tailocin scaffold to accommodate diverse receptor-binding domains, expanding its functionality to target a new type of receptor (capsule) and a previously untargeted species. In addition, functional tailocins with branched receptor-binding proteins portraying dual, cross-genus activity were produced. This work lays the groundwork for a scalable platform for the development of engineered tailocins, marking an important step towards making R2 tailocins a practical therapeutic tool for targeted bacterial infections.

microbiology↗

bioRxiv2024

The new SH3_T domain increases the structural and functional variability among SH3b-like CBDs from staphylococcal phage endolysins

Endolysins, proteins encoded by phages to lyse their hosts and release their progeny, have evolved to adapt to the structural features of each host. The endolysins from Staphylococcus-infecting phages typically feature complex architectures with two enzymatically active domains (EADs) and one cell wall-binding domain (CBD) belonging to the bacterial SH3 (SH3b) superfamily. This study focuses on three SH3b-like CBDs from exemplary staphylococcal phage endolysins (LysRODI, LysC1C, and LysIPLA5) that were structurally and functionally characterized. While RODI_CBD and C1C_CBD were assigned to the well-known SH3_5 family, a new family, SH3b_T, was identified using the CBD from LysIPLA5 as a model. GFP-fused CBDs were created to assess their differential binding to a collection of staphylococcal strains. IPLA5_CBD showed enhanced binding to Staphylococcus epidermidis, while RODI_CBD and C1C_CBD exhibited distinct binding profiles, with RODI_CBD targeting Staphylococcus aureus specifically and C1C_CBD displaying broad binding. Sequence comparisons suggested that a few differences in key amino acids could be responsible for the latter binding difference. The CBDs modulated the activity spectrum of synthetic EAD-CBD combinations in accordance with the previous binding profiles, but in a manner that was also dependent on the EAD present in the fusion protein. These results serve as a context for the diversity and versatility of SH3b domains in staphylococcal endolysins, providing insights on how (i) the CBDs from this superfamily have diverged to adapt to diverse bacterial ligands in spite of sharing a common fold; and (ii) the evolution of specificity relies on the EAD-CBD combination rather than solely the CBD. IMPORTANCEClinical management of bacterial infections is nowadays compromised by the rise in antimicrobial resistance. The development of new antimicrobial therapies with diverse modes of action is therefore of pivotal importance to complement the current standard of care. Phage endolysins are a new class of antibacterial agents based on rapid peptidoglycan degradation. The natural reservoir of phage endolysins offers a practically infinite diversity. This works reveals a broadly spread but still unknown phage endolysin domain targeting staphylococci while providing structural-functional insights that are paramount to understand the evolution of endolysins and how they can be applied as an antimicrobial.

molecular biology↗

bioRxiv2024

DepoScope: accurate phage depolymerase annotation and domain delineation using large language models

Bacteriophages (phages) are viruses that infect bacteria. Many of them produce specific enzymes called depolymerases to break down external polysaccharide structures. Accurate annotation and domain identification of these depolymerases are challenging due to their inherent sequence diversity. Hence, we present DepoScope, a machine learning tool that combines a fine-tuned ESM-2 model with a convolutional neural network to precisely identify depolymerase sequences and their enzymatic domains. To accomplish this, we curated a dataset from the INPHARED phage genome database, created a polysaccharide-degrading domain database, and applied sequential filters to construct a high-quality dataset, which are subsequently used to train DepoScope. Our work is the first approach that combines sequence-level predictions with amino-acid-level predictions for an accurate depolymerase detection and functional domain identification. In that way, we believe that DepoScope can enhance our understanding of phage-host interactions at the level of depolymerases. Summary with Key MessagesO_LIPhage depolymerases are proteins that play a crucial role in the first step of a phage replication cycle. As a result, they are both important from a biological perspective and a therapeutical perspective. C_LIO_LICurrent methods to accurately annotate phage depolymerases and their associated enzymatic domains remains challenging due to their inherent high sequence diversity. C_LIO_LIWe have developed DepoScope, a language-based artificial intelligence model that can accurately identify phage depolymerases and their specific enzymatic domains. C_LIO_LIWe provide full public access to the DepoScope code and database to give broad access to the research community and promote further research. C_LI

bioinformatics↗

bioRxiv2022

A bioluminescence-based ex vivo burn wound model for real-time assessment of novel antibacterial compounds

The silent pandemic of antibiotic resistance is thriving, prompting the urgent need for the development of new antibacterial drugs. However, within the preclinical pipeline, in vitro screening conditions can differ significantly from the final in vivo settings. To bridge the gap between in vitro and in vivo assays, we developed a pig skin-based bioluminescent ex vivo burn wound infection model, enabling real-time assessment of antibacterials in a longitudinal, non-destructive manner. We provide a proof-of-concept for A. baumannii NCTC13423, a multidrug-resistant clinical isolate, which was equipped with the luxCDABE operon as a reporter using a Tn7-based tagging system. This bioluminescence model provided a linear correlation between the number of bacteria and a broad dynamic range (104 to 109 CFU). This longitudinal model was subsequently validated using a fast-acting enzybiotic as an antibacterial. Since this model combines a realistic, clinically relevant yet strictly controlled environment with real-time measurement of bacterial burden, we put forward this ex vivo model as a valuable tool to assess the preclinical potential of novel antibacterial compounds. Summary statementHere, we demonstrate the potential of a bioluminescence-based ex vivo model for the longitudinal assessment of antibacterials. Moreover, we also provide a proof-of-concept with an engineered lysin.

molecular biology↗

bioRxiv2022

High resolution reconstruction of a Jumbo bacteriophage infecting capsulated bacteria using hyperbranched tail fibers

The Klebsiella jumbo myophage {phi}Kp24 displays an unusually complex arrangement of tail fibers interacting with a host cell. In this study, we combined cryo-electron microscopy methods, protein structure prediction methods, molecular simulations, and machine learning approaches to explore the capsid, tail, and tail fibers of this phage at high resolution. We determined the structure of the capsid and tail at 4.3[A] and 4.1[A] resolution. We observed that the tail fibers were highly branched and rearranged dramatically upon cell surface attachment. This complex configuration involves fourteen putative tail fibers with depolymerase activity that provide {phi}Kp24 with the ability to infect a broad panel of capsular polysaccharide (CPS) types of Klebsiella pneumoniae. Taken together, our study provides structural and functional insight into how {phi}Kp24 adapts to the highly variable surfaces of capsulated bacterial pathogens, which will be useful for the development of phage therapy approaches against pan-drug resistant K. pneumoniae strains.

microbiology↗

bioRxiv2019

Integrative omics analysis of Pseudomonas aeruginosa virus PA5oct highlights the molecular complexity of jumbo phages

Pseudomonas virus vB_PaeM_PA5oct is a compelling model phage to investigate phage-bacteria interactions and is a potent candidate for phage therapy. Combining hybrid genome sequencing, RNA-Seq, and mass spectrometry of virion-associated proteins allowed us to accurately assemble and annotate PA5octs 286,783 bp genome. It encodes 461 coding regions, of which 93 were identified as virion-associated proteins using ESI-MS/MS. RNA-seq revealed twelve tRNA genes, four ncRNA regions, and a gradual take-over of the total cell transcriptome from 21% in early infection to 93% in late infection. Although PA5oct is not organized into strictly contiguous regions of temporal transcription, defined genomic regions are expressed in early, middle, and late phases of infection. Interestingly, we observed distinct regions showing limited transcription activity throughout the infection cycle. The infection of Pseudomonas aeruginosa by PA5oct triggers the upregulation of bacterial operons related to NAD biosynthesis, Psl exopolysaccharide, and periplasmic nitrate reductase production and downregulates Type IV pili gene products, suggesting mechanisms of superinfection exclusion. We used the proteome of PA5oct to position this isolate amongst other phages using a protein-sharing network. This study expands our understanding of the molecular diversity of jumbo viruses and opens new questions towards cellular regulation and phage-encoded hijacking mechanisms.

molecular biology↗

bioRxiv2018

Innolysins: A novel approach to engineer endolysins to kill Gram-negative bacteria

Bacteriophage-encoded endolysins degrading the essential peptidoglycan of bacteria are promising alternative antimicrobials to handle the global threat of antibiotic resistant bacteria. However, endolysins have limited use against Gram-negative bacteria, since their outer membrane prevents access to the peptidoglycan. Here we present Innolysins, a novel concept for engineering endolysins that allows the enzymes to pass through the outer membrane, hydrolyse the peptidoglycan and kill the target bacterium. Innolysins combine the enzymatic activity of endolysins with the binding capacity of phage receptor binding proteins (RBPs). As our proof of concept, we used phage T5 endolysin and receptor binding protein Pb5, which binds irreversibly to the phage receptor FhuA involved in ferrichrome transport in Escherichia coli. In total, we constructed twelve Innolysins fusing endolysin with Pb5 or the binding domain of Pb5 with or without flexible linkers in between. While the majority of the Innolysins maintained their muralytic activity, Innolysin#6 also showed bactericidal activity against E. coli reducing the number of bacteria by 1 log, thus overcoming the outer membrane barrier. Using an E. coli fhuA deletion mutant, we demonstrated that FhuA is required for bactericidal activity, supporting that the specific binding of Pb5 to its receptor on E. coli is needed for the endolysin to access the peptidoglycan. Accordingly, Innolysin#6 was able to kill other bacterial species that carry conserved FhuA homologs such as Shigella sonnei and Pseudomonas aeruginosa. In summary, the Innolysin approach expands recent protein engineering strategies allowing customization of endolysins by exploiting phage RBPs to specifically target Gram-negative bacteria.\n\nIMPORTANCEThe extensive use of antibiotics has led to the emergence of antimicrobial resistant bacteria responsible for infections causing more than 50,000 deaths per year across Europe and the US. In response, the World Health Organization has stressed an urgent need to discover new antimicrobials to control in particular Gram-negative bacterial pathogens, due to their extensive multi-drug resistance. However, the outer membrane of Gram-negative bacteria limits the access of many antibacterial agents to their targets. Here, we developed a new approach, Innolysins that enable endolysins to overcome the outer membrane by exploiting the binding specificity of phage receptor binding proteins. As proof of concept, we constructed Innolysins against E. coli using the endolysin and the receptor binding protein of phage T5. Given the rich diversity of phage receptor binding proteins and their different binding specificities, our proof of concept paves the route for creating an arsenal of pathogen specific alternative antimicrobials.

microbiology↗