Biology subjects

Latka, A.

Publications and source records attributed to Latka, A..

4 recordsLinked to original sources

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↗

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↗

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↗