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|Enterobacteria phage HK97|
Group I (dsDNA)
HK97 is a bacterial virus, bacteriophage, known to infect Escherichia coli and related bacteria. It is named for the site of its isolation (Hong Kong). Like lambda phage and other lambdoid phages, HK97 has a double-stranded DNA genome.
Assembly and maturation
The capsid protein of HK97, gp5, cross-links upon maturation to form a concatenated chain-mail like structure. The bacteriophage undergoes a maturation process upon DNA packaging during which it expands by nearly 5 nm and changes from spherically symmetrical to icosahedrally symmetrical.
The HK97 assembly pathway begins with self-assembly of the capsid protein, gp5, into pentamers and hexamers. A protease, gp4, cleaves gp5 at its N-terminus. Attachment of a portal protein, gp3, coupled with conformational changes leads to formation of a prohead or procapsid structure. Further conformational changes and crosslinking of gp5 monomers comprise further capsid maturation and lead to formation of a mature phage head. Unlike most tailed viruses a scaffolding protein is not required for capsid assembly. However, studies on the effects of deleting the delta domain, or parts of it, indicates that it is essential for assembly.
- Helgstrand, Charlotte; Wikoff, William R; Duda, Robert L; Hendrix, Roger W; Johnson, John E; Liljas, Lars (1 December 2003). "The Refined Structure of a Protein Catenane: The HK97 Bacteriophage Capsid at 3.44Å Resolution". Journal of Molecular Biology. 334 (5): 885–899. doi:10.1016/j.jmb.2003.09.035.
- Hendrix, RW; Johnson, JE (2012). "Bacteriophage HK97 capsid assembly and maturation". Advances in Experimental Medicine and Biology. 726: 351–63. doi:10.1007/978-1-4614-0980-9_15. PMID 22297521.
- Duda RL, Martincic K, Hendrix RW (1995). "Genetic basis of bacteriophage HK97 prohead assembly". J. Mol. Biol. 247 (4): 636–47. doi:10.1006/jmbi.1994.0169. PMID 7723020.
- Oh B, Moyer CL, Hendrix RW, Duda RL (2014). "The delta domain of the HK97 major capsid protein is essential for assembly". Virology. 456-457: 171–8. doi:10.1016/j.virol.2014.03.022. PMC 4044616. PMID 24889236.