Bacteriophage ΦKZ (PhiKZ) is the archetype of a family of massive bacterial viruses. It is considered to have therapeutic potential as its host, Pseudomonas aeruginosa, is an opportunistic, intrinsically antibiotic resistant, pathogen that kills tens of thousands worldwide each year. ΦKZ is an incredibly interesting virus, expressing many systems that the host already possesses. On infection, it forms a 'nucleus', erecting a barrier around its genome to exclude host endonucleases and CRISPR-Cas systems. ΦKZ infection is independent of the host transcriptional apparatus. It expresses two different multi-subunit RNA polymerases (RNAPs): the virion RNAP (vRNAP) is injected with the viral DNA during infection to transcribe early genes, including those encoding the non-virion RNAP (nvRNAP), which transcribes all further genes. ΦKZ nvRNAP is formed by four polypeptides thought to represent homologues of the eubacterial β/β' subunits, and a fifth with unclear homology, but essential for transcription. We have resolved the structure of ΦKZ nvRNAP to better than 3.0 Å, shedding light on its assembly, homology, and the biological role of the fifth subunit: it is an embedded, integral member of the complex, the position, structural homology and biochemical role of which imply that it has evolved from an ancestral homologue to σ-factor.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8287921 | PMC |
http://dx.doi.org/10.1093/nar/gkab539 | DOI Listing |
J Mol Biol
September 2024
Shenzhen MSU-BIT University, 1 International University Park Road, Dayun New Town, Longgang District, Shenzhen, Guangdong Province 518172, People's Republic of China. Electronic address:
Viruses
October 2023
Research Center of Nanobiotechnologies, Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia.
A nucleus-like structure composed of phage-encoded proteins and containing replicating viral DNA is formed in cells infected by jumbo bacteriophage phiKZ. The PhiKZ genes are transcribed independently from host RNA polymerase (RNAP) by two RNAPs encoded by the phage. The virion RNAP (vRNAP) transcribes early viral genes and must be injected into the cell with phage DNA.
View Article and Find Full Text PDFNat Commun
June 2022
Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, 77555-0647, USA.
Recognition of promoters in bacterial RNA polymerases (RNAPs) is controlled by sigma subunits. The key sequence motif recognized by the sigma, the -10 promoter element, is located in the non-template strand of the double-stranded DNA molecule ~10 nucleotides upstream of the transcription start site. Here, we explain the mechanism by which the phage AR9 non-virion RNAP (nvRNAP), a bacterial RNAP homolog, recognizes the -10 element of its deoxyuridine-containing promoter in the template strand.
View Article and Find Full Text PDFNucleic Acids Res
July 2021
Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.
Bacteriophage ΦKZ (PhiKZ) is the archetype of a family of massive bacterial viruses. It is considered to have therapeutic potential as its host, Pseudomonas aeruginosa, is an opportunistic, intrinsically antibiotic resistant, pathogen that kills tens of thousands worldwide each year. ΦKZ is an incredibly interesting virus, expressing many systems that the host already possesses.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!