Tail-tape-fused virion and non-virion RNA polymerases of a thermophilic virus with an extremely long tail

Abstract

Thermus thermophilus bacteriophage P23-45 encodes a giant 5,002-residue tail tape measure protein (TMP) that defines the length of its extraordinarily long 800 nm tail. We found that the N-terminal portion of P23-45 TMP is an unusual RNA polymerase (RNAP) homologous to cellular and viral two-barrel RNAPs. The TMP-fused virion RNAP transcribes pre-early phage genes, including a gene that encodes another, non-virion RNAP, that transcribes early and some middle phage genes. We determined the crystal structures of both P23-45 RNAPs. The non-virion RNAP has a crab claw-like architecture similar to previously reported two-barrel RNAPs. The virion RNAP adopts a unique flat structure without a clamp, which likely reflects the requirement for its extrusion through the narrow channel in the phage tail for delivery into the cell. Structure and sequence comparisons of the P23-45 RNAPs with other phage and cellular RNAPs suggest that, despite the extensive functional differences, the two P23-45 RNAPs originate from an ancient gene duplication in an ancestral phage. Our findings demonstrate remarkable adaptability of two-barrel RNAPs that can be attained within a single virus species.

Atomic structures of a bacteriocin targeting Gram-positive bacteria

“…In addition to their primary function of determining the length of the phage tail, phage TMPs are involved in a myriad of other secondary, host-related functions after ejection from the tail tube lumen: particular amino acid sequences were identified as peptidases responsible for degrading the host cell wall 28,32,33 , RNA polymerases used for transcribing DNA 34 , and TM domains facilitating the formation of a channel on the inner membrane for DNA translocation into the host cell 35 . Like the diffocin TMP, the TMPs of Gram-positive-targeting phages phiCD119, TP901-1 and P2 also have a predicted TM region (Fig.…”

Refining the transcriptional landscapes for distinct clades of virulent phages infecting Pseudomonas aeruginosa

“…Of these, ONT-cappable-seq is a recent, long-read, nanopore-based cDNA sequencing method that permits end-to-end sequencing of primary prokaryotic transcripts, concurrently delineating both 5′ and 3′ RNA extremities, and revealing operon structures. Recently, ONT-cappable-seq was successfully introduced to study the transcriptomes and RNA biology of P. aeruginosa phages LUZ7 ( Luzseptimavirus ) and LUZ100 (unclassified Autographiviridae ) (Putzeys et al 2022 , 2023a ) and Thermus thermophilus phage P23-45 ( Oshimavirus ) (Chaban et al 2022 ), yielding high-resolution genome-wide maps of their transcription start sites (TSS), transcription terminator sites (TTS), and transcription unit (TU) architectures.…”

Refining the transcriptional landscapes for distinct clades of virulent phages infectingpseudomonas aeruginosa

“…Recently, ONT-cappable-seq was successfully introduced to study the transcriptomes and RNA biology of Pseudomonas aeruginosa phages LUZ7 ( Luzseptimavirus ) and LUZ100 (unclassified Autographiviridae ) (Putzeys et al . 2022, 2023) and Thermus thermophilus phage P23-45 ( Oshimavirus ) (Chaban et al . 2022), yielding high-resolution genome-wide maps of their transcription start sites (TSS), transcription terminator sites (TTS) and transcription unit (TU) architectures.…”