biostudies-literatureUnknown16Shitikov E<h4>Introduction</h4>The growing prevalence of multidrug-resistant <i>Mycobacterium tuberculosis</i> and nontuberculous mycobacteria (NTM) highlights the urgent need for alternative therapeutic approaches. Mycobacteriophages, viruses that selectively infect mycobacteria, have emerged as promising tools. Here, we report the isolation and characterization of a new subcluster K4 phage, Yasnaya_Polyana, with a focus on its regulatory motifs and engineered lytic variant.<h4>Methods</h4>The phage was isolated by enrichment on <i>Mycobacterium smegmatis</i> mc(2)155, followed by genome sequencing and functional annotation. Start-Associated Sequences (SAS) and Extended SAS (ESAS) were analyzed <i>in silico</i> across 188 cluster K phages. A lytic derivative, YPΔ47, was engineered by deleting the rFrontiers in microbiology1713073https://www.ebi.ac.uk/biostudies/studies/S-EPMC12699233biostudies-literatureMycobacteriophage Yasnaya_Polyana and its engineered lytic derivative: specificity of regulatory motifs and lytic potential.PMC12699233Shitikov EBespiatykh DShleeva MLebedeva AVnukova AKiselev SKazyulina ABagrov DGorodnichev RMalakhova MKuznetsova SZaychikova MKlimina KKornienko MGerman AFursov MStrokach AfalseMycobacteriophage Yasnaya_Polyana and its engineered lytic derivative: specificity of regulatory motifs and lytic potential.<h4>Introduction</h4>The growing prevalence of multidrug-resistant <i>Mycobacterium tuberculosis</i> and nontuberculous mycobacteria (NTM) highlights the urgent need for alternative therapeutic approaches. Mycobacteriophages, viruses that selectively infect mycobacteria, have emerged as promising tools. Here, we report the isolation and characterization of a new subcluster K4 phage, Yasnaya_Polyana, with a focus on its regulatory motifs and engineered lytic variant.<h4>Methods</h4>The phage was isolated by enrichment on <i>Mycobacterium smegmatis</i> mc(2)155, followed by genome sequencing and functional annotation. Start-Associated Sequences (SAS) and Extended SAS (ESAS) were analyzed <i>in silico</i> across 188 cluster K phages. A lytic derivative, YPΔ47, was engineered by deleting the r2025-01-01T00:00:00Z20252026-07-15T12:07:06.279Z2026-07-04T03:12:27.804ZS-EPMC126992334139549310.3389/fmicb.2025.1713073