Bacteriophage HK97

{{Redirect|HK97|other uses|Hong Kong 97 (disambiguation){{!}}Hong Kong 97}}

{{virusbox

| name = Bacteriophage HK97

| image = File:BacteriophageHK97.jpg

| image_caption = Bacteriophage HK97 as seen in transmission electron microscopy (TEM), with magnification 300000x.

| image_alt = A transmission electron micrograph of bacteriophage HK97

| parent = Byrnievirus

| species = Byrnievirus HK97{{cite web|title=History of the taxon: Species: Byrnievirus HK97 (2024 Release, MSL #40)|url=https://ictv.global/taxonomy/taxondetails?taxnode_id=202401071&taxon_name=Byrnievirus%20HK97|publisher=International Committee on Taxonomy of Viruses|access-date=11 April 2025}}

| synonyms =

Bacteriophage HK97
Phage HK97
HK97 bacteriophage
HK97 phage
Escherichia phage HK97
Escherichia virus HK97

}}

Bacteriophage HK97, often shortened to HK97, is a species of virus that infects Escherichia coli and related bacteria. It is named after Hong Kong (HK), where it was first located. HK97 has a double-stranded DNA genome.

Assembly and maturation

The major capsid protein of HK97, called gp5, cross-links upon maturation to form a chain-mail like structure.{{cite journal|last=Helgstrand|first=Charlotte|author2=Wikoff, William R |author3=Duda, Robert L |author4=Hendrix, Roger W |author5=Johnson, John E |author6= Liljas, Lars |title=The Refined Structure of a Protein Catenane: The HK97 Bacteriophage Capsid at 3.44Å Resolution|journal=Journal of Molecular Biology|date=1 December 2003|volume=334|issue=5|pages=885–899|doi=10.1016/j.jmb.2003.09.035|pmid=14643655}} While DNA is being packaged into the capsid, the capsid expands by nearly 5 nm and changes from spherical to icosahedral in shape.{{cn|date=October 2022}}

The HK97 assembly pathway begins with self-assembly of gp5 into pentamers and hexamers. A protease, called gp4, cleaves gp5 at its N-terminus. Attachment of a portal protein, gp3, coupled with conformational changes leads to the formation of a prohead, or procapsid, which is the precursor to the mature capsid.{{cite book|last=Hendrix|first=RW|author2=Johnson, JE|title=Viral Molecular Machines |chapter=Bacteriophage HK97 Capsid Assembly and Maturation |series=Advances in Experimental Medicine and Biology |year=2012|volume=726|pages=351–63|pmid=22297521|doi=10.1007/978-1-4614-0980-9_15|isbn=978-1-4614-0979-3}}

A scaffolding protein is not required for capsid assembly.{{cite journal |vauthors=Duda RL, Martincic K, Hendrix RW |title=Genetic basis of bacteriophage HK97 prohead assembly |journal=J. Mol. Biol. |volume=247 |issue=4 |pages=636–47 |year=1995 |pmid=7723020 |doi=10.1006/jmbi.1994.0169 }} 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.{{cite journal |vauthors=Oh B, Moyer CL, Hendrix RW, Duda RL |title=The delta domain of the HK97 major capsid protein is essential for assembly |journal=Virology |volume=456-457 |pages=171–8 |year=2014 |pmid=24889236 |pmc=4044616 |doi=10.1016/j.virol.2014.03.022 }}

Bacteriophage HK97

Assembly and maturation

References

Further reading