''Escherichia virus HK97'', often shortened to HK97, is a species of

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...

that infects ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...

'' and related

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

. It is named after

Hong Kong Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China ( abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delt ...

(HK), where it was first located. HK97 has a double-stranded DNA genome.

Assembly and maturation

The major

capsid A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may ...

protein of HK97, called gp5, cross-links upon maturation to form a

chain-mail Chain mail (properly called mail or maille but usually called chain mail or chainmail) is a type of armour consisting of small metal rings linked together in a pattern to form a mesh. It was in common military use between the 3rd century BC and ...

like structure. While DNA is being packaged into the capsid, the capsid expands by nearly 5 nm and changes from spherical to icosahedral in shape. The HK97 assembly pathway begins with self-assembly of gp5 into pentamers and hexamers. A protease, called gp4, cleaves gp5 at its

N-terminus The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

. Attachment of a portal protein, gp3, coupled with conformational changes leads to the formation of a

prohead A prohead or procapsid is an immature viral capsid structure formed in the early stages of self-assembly of some bacteriophages, including the ''Caudovirales ''Caudovirales'' is an order of viruses known as the tailed bacteriophages (''cauda' ...

, or procapsid, which is the precursor to the mature capsid. A

scaffolding protein In biology, scaffold proteins are crucial regulators of many key signalling pathways. Although scaffolds are not strictly defined in function, they are known to interact and/or bind with multiple members of a signalling pathway, tethering them in ...

is not required for capsid assembly. However, studies on the effects of deleting the delta domain of the major capsid protein, or parts of it, indicate that it is essential for assembly.

References

External links

UniProt Taxonomy: Enterobacteria phage HK97
{{DEFAULTSORT:Hk97 Siphoviridae

Assembly and maturation

References

Further reading

External links