Fold first, ask later: structure-informed function annotation of phage proteins.

Phages, the viruses of bacteria, harbor an incredibly diverse repertoire of proteins capable of manipulating their bacterial hosts, inspiring many medical and biotechnological applications. However, to date, only a limited subset of that repertoire can be exploited, due to the difficulties in functionally elucidating these proteins. In this study, we investigated several structure-informed approaches to annotate hypothetical proteins from infecting phages.

Acetylomics reveals an extensive acetylation diversity within .

Bacteria employ a myriad of regulatory mechanisms to adapt to the continuously changing environments that they face. They can, for example, use post-translational modifications, such as Nε-lysine acetylation, to alter enzyme activity. Although a lot of progress has been made, the extent and role of lysine acetylation in many bacterial strains remains uncharted.

Targeted Genome Editing of Virulent Pseudomonas Phages Using CRISPR-Cas3.

The vast number of unknown phage-encoded ORFan genes and limited insights into the genome organization of phages illustrate the need for efficient genome engineering tools to study bacteriophage genes in their natural context. In addition, there is an application-driven desire to alter phage properties, which is hampered by time constraints for phage genome engineering in the bacterial host. We here describe an optimized CRISPR-Cas3 system in Pseudomonas for straightforward editing of the genome of virulent bacteriophages.

Posttranslational modifications in bacteria during phage infection.

During phage infection, both virus and bacteria attempt to gain and/or maintain control over critical bacterial functions, through a plethora of strategies. These strategies include posttranslational modifications (PTMs, including phosphorylation, ribosylation, and acetylation), as rapid and dynamic regulators of protein behavior. However, to date, knowledge on the topic remains scarce and fragmented, while a more systematic investigation lies within reach.

FLAMS: Find Lysine Acylations and other Modification Sites.

Summary: Today, hundreds of post-translational modification (PTM) sites are routinely identified at once, but the comparison of new experimental datasets to already existing ones is hampered by the current inability to search most PTM databases at the protein residue level. We present FLAMS (Find Lysine Acylations and other Modification Sites), a Python3-based command line and web-tool that enables researchers to compare their PTM sites to the contents of the CPLM, the largest dedicated protein lysine modification database, and dbPTM, the most comprehensive general PTM database, at the residue level. FLAMS can be integrated into PTM analysis pipelines, allowing researchers to quickly assess the novelty and conservation of PTM sites across species in newly generated datasets, aiding in the functional assessment of sites and the prioritization of sites for further experimental characterization.

A SEVA-based, CRISPR-Cas3-assisted genome engineering approach for with efficient vector curing.

The CRISPR-Cas3 editing system as presented here facilitates the creation of genomic alterations in and in a straightforward manner. By providing the Cas3 system as a vector set with Golden Gate compatibility and different antibiotic markers, as well as by employing the established Standard European Vector Architecture (SEVA) vector set to provide the homology repair template, this system is flexible and can readily be ported to a multitude of Gram-negative hosts. Besides genome editing, the Cas3 system can also be used as an effective and universal tool for vector curing.

The phage-encoded protein PIT2 impacts quorum sensing by direct interaction with LasR.

In recent decades, there has been a notable increase in antibiotic-resistant isolates, necessitating the development of innovative treatments to combat this pathogen. This manuscript explores the potential of different phage proteins to attenuate virulence factors of , particularly the type II secretion system (T2SS). PIT2, a protein derived from the lytic phage LMA2 inhibits the T2SS effectors PrpL and LasA and attenuates the bacterial virulence toward HeLa cells and .

Metabolic reprogramming of Pseudomonas aeruginosa by phage-based quorum sensing modulation.

The Pseudomonas quinolone signal (PQS) is a multifunctional quorum sensing molecule of key importance to P. aeruginosa. Here, we report that the lytic Pseudomonas bacterial virus LUZ19 targets this population density-dependent signaling system by expressing quorum sensing targeting protein (Qst) early during infection.

Bacteriophage-mediated interference of the c-di-GMP signalling pathway in Pseudomonas aeruginosa.

C-di-GMP is a key signalling molecule which impacts bacterial motility and biofilm formation and is formed by the condensation of two GTP molecules by a diguanylate cyclase. We here describe the identification and characterization of a family of bacteriophage-encoded peptides that directly impact c-di-GMP signalling in Pseudomonas aeruginosa. These phage proteins target Pseudomonas diguanylate cyclase YfiN by direct protein interaction (termed YIPs, YfiN Interacting Peptides).

qDNase assay: A quantitative method for real-time assessment of DNase activity on coated surfaces.

DNase coatings show great potential to prevent biofilm formation in various applications of the medical implant, food and marine industry. However, straightforward and quantitative methods to characterize the enzymatic activity of these coatings are currently not available. We here introduce the qDNase assay, a quantitative, real-time method to characterize the activity of DNase coatings.

Phage-based target discovery and its exploitation towards novel antibacterial molecules.

The deeply intertwined evolutionary history between bacteriophages and bacteria has endowed phages with highly specific mechanisms to hijack bacterial cell metabolism for their propagation. Here, we present a comprehensive, phage-driven strategy to reveal novel antibacterial targets by the exploitation of phage-bacteria interactions. This strategy will enable the design of small molecules, which mimic the inhibitory phage proteins, and allow the subsequent hit-to-lead development of these antimicrobial compounds.

The Phage-Encoded -Acetyltransferase Rac Mediates Inactivation of Transcription by Cleavage of the RNA Polymerase Alpha Subunit.

In this study, we describe the biological function of the phage-encoded protein RNA polymerase alpha subunit cleavage protein (Rac), a predicted Gcn5-related acetyltransferase encoded by phiKMV-like viruses. These phages encode a single-subunit RNA polymerase for transcription of their late (structure- and lysis-associated) genes, whereas the bacterial RNA polymerase is used at the earlier stages of infection. Rac mediates the inactivation of bacterial transcription by introducing a specific cleavage in the α subunit of the bacterial RNA polymerase.

Phage S144, A New Polyvalent Phage Infecting spp. and .

Phages are generally considered species- or even strain-specific, yet polyvalent phages are able to infect bacteria from different genera. Here, we characterize the novel polyvalent phage S144, a member of the genus. By screening 211 strains, we found that phage S144 forms plaques on specific serovars of subsp.

Isolation and Characterization of Phage vB_PatM_CB7: New Insights into the Genus .

To date, is one of two genera of bacteriophage (phage), with phages infecting , an economically important phytopathogen that causes potato blackleg and soft rot disease. This study provides a detailed description of phage CB7 (vB_PatM_CB7), which specifically infects . Host range, morphology, latent period, burst size and stability at different conditions of temperature and pH were examined.

A Tailspike with Exopolysaccharide Depolymerase Activity from a New Providencia stuartii Phage Makes Multidrug-Resistant Bacteria Susceptible to Serum-Mediated Killing.

is emerging as a significant drug-resistant nosocomial pathogen, which encourages the search for alternative therapies. Here, we have isolated phage Stuart, a novel podovirus infecting multidrug-resistant hospital isolates of this bacterium. Phage Stuart is a proposed member of a new subfamily genus, with a 41,218-bp genome, direct 345-bp repeats at virion DNA ends, and limited sequence similarity of proteins to proteins in databases.

Screening for Growth-Inhibitory ORFans in Pseudomonas aeruginosa-Infecting Bacteriophages.

Like all viruses, bacteriophages heavily depend on their host's physiology for reproduction. Therefore, phages have evolved numerous proteins that influence the host metabolism to facilitate the infection process. Some of these proteins strongly perturb the host cell, ultimately leading to cell death.

Analyzing Phage-Host Protein-Protein Interactions Using Strep-tag II Purifications.

After injecting their genome into the bacterial host cell, bacteriophages need to convert the host metabolism toward efficient phage production. For this, specific proteins have evolved which interact with key host proteins to inhibit, activate or redirect the function of these proteins. Since 70% of the currently annotated phage genes are hypothetical proteins of unknown function, the identification and characterization of these phage proteins involved in host-phage protein-protein interactions remains challenging.

Novel N4-Like Bacteriophages of Pectobacterium atrosepticum.

is an economically important phytopathogen that is responsible for potato blackleg and soft rot, and for which current control strategies are limited. In this study, stem samples of potato crops exhibiting blackleg were taken from three farms in Co. Cork, Ireland, and they were found to be infected with .

A Lytic Providencia rettgeri Virus of Potential Therapeutic Value Is a Deep-Branching Member of the Genus.

is emerging as a new opportunistic pathogen with high antibiotic resistance. The need to find alternative methods to control antibiotic-resistant bacteria and the recent advances in phage therapy motivate the search for new phages able to infect spp. This study describes the isolation and characterization of an obligatory lytic phage, vB_PreS_PR1 (PR1), with therapeutic potential against drug-resistant PR1 is a siphovirus.

Pseudomonas predators: understanding and exploiting phage-host interactions.

Species in the genus Pseudomonas thrive in a diverse set of ecological niches and include crucial pathogens, such as the human pathogen Pseudomonas aeruginosa and the plant pathogen Pseudomonas syringae. The bacteriophages that infect Pseudomonas spp. mirror the widespread and diverse nature of their hosts.

Characterization and genomic analyses of two newly isolated Morganella phages define distant members among Tevenvirinae and Autographivirinae subfamilies.

Morganella morganii is a common but frequent neglected environmental opportunistic pathogen which can cause deadly nosocomial infections. The increased number of multidrug-resistant M. morganii isolates motivates the search for alternative and effective antibacterials.

Things Are Getting Hairy: Enterobacteria Bacteriophage vB_PcaM_CBB.

Enterobacteria phage vB_PcaM_CBB is a "jumbo" phage belonging to the family . It possesses highly atypical whisker-like structures along the length of its contractile tail. It has a broad host range with the capability of infecting species of the genera , and .

Viral interference of the bacterial RNA metabolism machinery.

In a recent publication, we reported a unique interaction between a protein encoded by the giant myovirus phiKZ and the Pseudomonas aeruginosa RNA degradosome. Crystallography, site-directed mutagenesis and interactomics approaches revealed this 'degradosome interacting protein' or Dip, to adopt an 'open-claw' dimeric structure that presents acidic patches on its outer surface which hijack 2 conserved RNA binding sites on the scaffold domain of the RNase E component of the RNA degradosome. This interaction prevents substrate RNAs from being bound and degraded by the RNA degradosome during the virus infection cycle.

Structural elucidation of a novel mechanism for the bacteriophage-based inhibition of the RNA degradosome.

In all domains of life, the catalysed degradation of RNA facilitates rapid adaptation to changing environmental conditions, while destruction of foreign RNA is an important mechanism to prevent host infection. We have identified a virus-encoded protein termed gp37/Dip, which directly binds and inhibits the RNA degradation machinery of its bacterial host. Encoded by giant phage фKZ, this protein associates with two RNA binding sites of the RNase E component of the Pseudomonas aeruginosa RNA degradosome, occluding them from substrates and resulting in effective inhibition of RNA degradation and processing.