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Structure of the urea-treated empty bacteriophage T5 portal complex
Structural highlights
FunctionPORTL_BPT5 Forms the portal vertex of the capsid and plays a role in governing correct capsid geometry (PubMed:26616586). This portal plays critical roles in capsid assembly, genome packaging, head completion protein attachment, and genome ejection (By similarity). The portal protein multimerizes as a single ring-shaped homododecamer arranged around a central channel (By similarity). Binds to the terminase subunits to form the packaging machine (By similarity).[UniProtKB:P25480][1] Publication Abstract from PubMedT5 is a siphophage that has been extensively studied by structural and biochemical methods. However, the complete in situ structures of T5 before and after DNA ejection remain unknown. In this study, we used cryo-electron microscopy (cryo-EM) to determine the structures of mature T5 (a laboratory-adapted, fiberless T5 mutant) and urea-treated empty T5 (lacking the tip complex) at near-atomic resolutions. Atomic models of the head, connector complex, tail tube, and tail tip were built for mature T5, and atomic models of the connector complex, comprising the portal protein pb7, adaptor protein p144, and tail terminator protein p142, were built for urea-treated empty T5. Our findings revealed that the aforementioned proteins did not undergo global conformational changes before and after DNA ejection, indicating that these structural features were conserved among most myophages and siphophages. The present study elucidates the underlying mechanisms of siphophage infection and DNA ejection. Structures of Mature and Urea-Treated Empty Bacteriophage T5: Insights into Siphophage Infection and DNA Ejection.,Peng Y, Tang H, Xiao H, Chen W, Song J, Zheng J, Liu H Int J Mol Sci. 2024 Aug 3;25(15):8479. doi: 10.3390/ijms25158479. PMID:39126049[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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