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Virus DNA translocation: progress towards a first ascent of Mount Pretty Difficult
Author(s) -
Maluf Nasib K.,
Feiss Michael
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05214.x
Subject(s) - biology , chromosomal translocation , mount , virology , virus , computational biology , dna , microbiology and biotechnology , genetics , gene , computer science , operating system
Summary Virion DNA molecules of large dsDNA viruses are highly condensed. To pack the DNA, an ATP hydrolysis‐powered motor translocates the DNA into a preformed empty protein shell, the prohead. The icosahedral prohead has a special fivefold vertex, the portal vertex, where the translocation machinery acts. The portal vertex contains the portal protein, a gear‐shaped dodecamer of radially disposed subunits with a central channel for DNA entry. The symmetry mismatch between the fivefold symmetry of the shell vertex and the 12‐fold symmetry of the portal protein has prompted DNA packaging models in which ATP‐driven portal protein rotation drives DNA translocation. In this issue of Molecular Microbiology , Baumann and colleagues test portal rotation models using bacteriophage T4. A fusion between the gp20 portal protein and the HOC external shell decoration protein is used to create a block to portal rotation. Finding that DNA packaging is unimpeded in proheads containing the fusion argues that portal rotation is not crucial to DNA translocation. The paper is a landmark for describing direct testing of the mechanism of DNA translocation.