8zvi
From Proteopedia
Structure of the bacteriophage T5 capsid
Structural highlights
FunctionCAPSD_BPT5 Major capsid protein that self-associates to form 120 hexamers and 11 pentamers, building the T=13 icosahedral capsid which about 860 Angstroms in diameter. Responsible for its self-assembly into a procapsid. The phage does not need to encode a separate scaffolfing protein because its capsid protein contains the delta domain that carries that function. The capsid gains its final stability through the reorganization of the subunits that takes place upon expansion. DNA encapsidation through the portal triggers capsid expansion and the binding of the decoration protein to the capsid exterior.[1] [2] [3] 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[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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