A unique feature found in the genomes of mycobacteriophages such as L5 belonging to the A cluster is the presence of multiple dispersed repeated elements known as stoperators. The phage repressor binds these repeat elements, shutting off transcription globally and thereby promoting lysogeny. Interestingly, the sequence of these stoperators closely matches that of the consensus -35 region of prokaryotic promoters, leading us to propose that they may have a role to play in the initiation of transcription by serving as RNA polymerase binding sites.
View Article and Find Full Text PDFMutation is a phenomenon inescapable for all life-forms, including bacteria. While bacterial mutation rates are generally low due to the operation of error-avoidance systems, sometimes they are elevated by many orders of magnitude. Such a state, known as a hypermutable state, can result from exposure to stress or to harmful environments.
View Article and Find Full Text PDFMycobacteriophage D29 infects species belonging to the genus Mycobacterium including the deadly pathogen Mycobacterium tuberculosis. D29 is a lytic phage, although, related to the lysogenic mycobacteriophage L5. This phage is unable to lysogenize in mycobacteria as it lacks the gene encoding the phage repressor.
View Article and Find Full Text PDFBL21-AI is a commercially available strain possessing a phage T7-based protein-expression system. A combination of tight regulation and high yield makes it widely used for high-level expression of toxic recombinant proteins. Here, we present the complete genome sequence of BL21-AI and provide insights on its genome.
View Article and Find Full Text PDFMycobacteriophage D29 is a lytic phage that infects various species of Mycobacterium including M. tuberculosis. Its genome has 77 genes distributed almost evenly between two converging operons designated as left and right.
View Article and Find Full Text PDFVitamin C is known to inhibit mycobacterial growth by acting as a hypoxia inducing agent. While investigating how mycobacteriophage growth is influenced by hypoxic conditions induced by vitamin C, using Mycobacterium smegmatis- mycobacteriophage D29 as a model system, it was observed that prior exposure of the host to such conditions resulted in increased burst size of the phage. Vitamin C pre-exposure was also found to induce synchronous growth of the host.
View Article and Find Full Text PDFMycobacteriophage D29 encodes a protein Gp66 which has been predicted to be a calcineurin family phosphoesterase. Phylogenetically Gp66 and related proteins mostly derived from mycobacteriophages form a distinct clade within this family. Interestingly, the presence of gene 66 orthologs can be traced to bacteria of diverse phylogenetic lineages such as Aquifex aeolicus, a deep branching eubacteria and Methanococcus jannaschii, an archaebacteria.
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