The putative small terminase from the thermophilic dsDNA bacteriophage G20C is a nine-subunit oligomer

Loredo-Varela, Juan Luis; Chechik, M.; Levdikov, V.M.; Abd-El-Aziz, Ahmad; Minakhin, Leonid; Severinov, Konstantin; Smits, C.; Antson, A.A.

doi:10.1107/s1744309113017016

Cited by 8 publications

(7 citation statements)

References 15 publications

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“…Typically, the small terminase subunit specifically recognizes viral DNA and recruits the large terminase protein for the initial cleavage. The large terminase subunit has an ATPase activity that provides energy for packaging initiation and termination [36],[37]. Portal protein (encoded by ORF77) shares high amino acid sequence similarity with Staphylococcus phage vB_SepS_SEP9, which can inject DNA into the host cell through a pathway formed by portal protein [38].…”

Section: Resultsmentioning

confidence: 99%

Isolation and characterization of the <em>Staphylococcus aureus</em> bacteriophage vB_SauS_SA2

Wang¹,

Zhao²,

Sun³

et al. 2019

AIMS Microbiology

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A novel bacteriophage vB_SauS_SA2 (hereafter designated SA2) that infects Staphylococcus aureus was isolated. At a multiplicity of infection (MOI) of 0.1, phage SA2 had a latent period of about 10 min with a burst size of 293 PFUs/infected cell (PFU, plaque forming unit). Phage SA2 had a double-stranded DNA genome with a length of 89,055 bp and a G + C content of 31.9%. The genome contained 130 open reading frames (ORFs), 28 of which had assigned functions, and 18 were unique. One tRNA gene (tRNAAsn) was discovered, and no virulence genes were identified. Its genome showed very low similarity with phage genomes deposited in public databases (75% nucleotide identity and 7% query coverage). The unique characteristics of phage SA2 led to the proposal of a new Siphoviridae genus named ‘SA2likevirus’.

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Section: Resultsmentioning

confidence: 99%

Isolation and characterization of the <em>Staphylococcus aureus</em> bacteriophage vB_SauS_SA2

Wang¹,

Zhao²,

Sun³

et al. 2019

AIMS Microbiology

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“…P23-45 and P74-26 belong to the genus P23virus , and are closely related to bacteriophage G20c, all of which infect Thermus thermophilus (20). Individual components of the DNA packaging motor of these viruses have been characterized biochemically and structurally (21–24). We isolated procapsids and expanded capsids of P23-45 and demonstrated DNA packaging in vitro in the presence of cognate large terminase gp85.…”

mentioning

confidence: 99%

Cryo-EM structure and in vitro DNA packaging of a thermophilic virus with supersized T=7 capsids

Bayfield

Klimuk

Winkler

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Double-stranded DNA viruses, including bacteriophages and herpesviruses, package their genomes into preformed capsids, using ATP-driven motors. Seeking to advance structural and mechanistic understanding, we established in vitro packaging for a thermostable bacteriophage, P23-45 of Thermus thermophilus. Both the unexpanded procapsid and the expanded mature capsid can package DNA in the presence of packaging ATPase over the 20 °C to 70 °C temperature range, with optimum activity at 50 °C to 65 °C. Cryo-EM reconstructions for the mature and immature capsids at 3.7-Å and 4.4-Å resolution, respectively, reveal conformational changes during capsid expansion. Capsomer interactions in the expanded capsid are reinforced by formation of intersubunit β-sheets with N-terminal segments of auxiliary protein trimers. Unexpectedly, the capsid has T=7 quasi-symmetry, despite the P23-45 genome being twice as large as those of known T=7 phages, in which the DNA is compacted to near-crystalline density. Our data explain this anomaly, showing how the canonical HK97 fold has adapted to double the volume of the capsid, while maintaining its structural integrity. Reconstructions of the procapsid and the expanded capsid defined the structure of the single vertex containing the portal protein. Together with a 1.95-Å resolution crystal structure of the portal protein and DNA packaging assays, these reconstructions indicate that capsid expansion affects the conformation of the portal protein, while still allowing DNA to be packaged. These observations suggest a mechanism by which structural events inside the capsid can be communicated to the outside.

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“…The structure of several TerSs from bacteriophage and HSV-1 has been investigated using biophysical methods, providing a useful framework for understanding their assembly and activity. Three-dimensional structures have been obtained for TerS from bacteriophages that infect Escherichia coli (i.e., λ [ 58 ], T4-like 44RR [ 59 ], HK97 [ 60 ]), Shigella flexneri (i.e., Sf6 [ 61 , 62 ]), Salmonella enterica (i.e., P22 [ 63 , 64 , 65 , 66 ]), Bacillus subtilis (i.e., SF6, SPP1 [ 67 ]), Pseudomonas aeruginosa (i.e., PaP3 [ 68 ], NV1 [ 68 ], E217 [ 28 ]), and Thermus thermophilus (i.e., G20c [ 69 ], P74–26 [ 70 ]) ( Table 1 ). All atomic structures of phage TerSs reported between 2002 and 2019 were solved using X-ray methods or used NMR for a fragment of phage λ TerS [ 58 ].…”

Section: Diversification Of the Ters Fold And Oligomeric State In Bac...mentioning

confidence: 99%

Viral Small Terminase: A Divergent Structural Framework for a Conserved Biological Function

Lokareddy

Hou

et al. 2022

Viruses

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The genome packaging motor of bacteriophages and herpesviruses is built by two terminase subunits, known as large (TerL) and small (TerS), both essential for viral genome packaging. TerL structure, composition, and assembly to an empty capsid, as well as the mechanisms of ATP-dependent DNA packaging, have been studied in depth, shedding light on the chemo-mechanical coupling between ATP hydrolysis and DNA translocation. Instead, significantly less is known about the small terminase subunit, TerS, which is dispensable or even inhibitory in vitro, but essential in vivo. By taking advantage of the recent revolution in cryo-electron microscopy (cryo-EM) and building upon a wealth of crystallographic structures of phage TerSs, in this review, we take an inventory of known TerSs studied to date. Our analysis suggests that TerS evolved and diversified into a flexible molecular framework that can conserve biological function with minimal sequence and quaternary structure conservation to fit different packaging strategies and environmental conditions.

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The putative small terminase from the thermophilic dsDNA bacteriophage G20C is a nine-subunit oligomer

Cited by 8 publications

References 15 publications

Isolation and characterization of the <em>Staphylococcus aureus</em> bacteriophage vB_SauS_SA2

Isolation and characterization of the <em>Staphylococcus aureus</em> bacteriophage vB_SauS_SA2

Cryo-EM structure and in vitro DNA packaging of a thermophilic virus with supersized T=7 capsids

Viral Small Terminase: A Divergent Structural Framework for a Conserved Biological Function

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