The C-terminal domain of the bacteriophage T4 terminase docks on the prohead portal clip region during DNA packaging
The C-terminal domain of the bacteriophage T4 terminase docks on the prohead portal clip region during DNA packaging
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DOI：
10.1016/j.virol.2013.07.011
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发表时间：
2013-11-01
期刊：
影响因子：
3.7
通讯作者：
Black, Lindsay W.
中科院分区：
文献类型：
--
作者：
Dixit, Aparna Banerjee;Ray, Krishanu;Black, Lindsay W.
Bacteriophage ATP-based packaging motors translocate DNA into a pre-formed prohead through a dodecameric portal ring channel to high density. We investigated portal-terminase docking interactions at specifically localized residues within a terminase-interaction region (aa279-316) in the phage T4 portal protein gp20 equated to the clip domain of the SPP1 portal crystal structure by 3D modeling. Within this region, three residues allowed A to C mutations whereas three others did not, consistent with informatics analyses showing the tolerated residues are not strongly conserved evolutionarily. About 7.5 nm was calculated by FCS-FRET studies employing maleimide Alexa488 dye labeled A316C proheads and gp17 CT-ReAsH supporting previous work docking the C-terminal end of the T4 terminase (gp17) closer to the N-terminal GFP-labeled portal (gp20) than the N-terminal end of the terminase. Such a terminase-portal orientation fits better to a proposed "DNA crunching" compression packaging motor and to portal determined DNA headful cutting. (C) 2013 Elsevier Inc. All rights reserved.
