Minor spike protein (IPR006777)

Short name: Microvir_H

Overlapping homologous superfamilies


Family relationships



This entry represents the minor spike protein (also known as H protein), which is a minor spike component of the viral shell. It is involved in the ejection of the phage DNA in the host and is injected with the DNA in the periplasmic space of the host. It is involved in the determination of the phage host-range [PMID: 10739948, PMID: 16143459].

Bacteriophage PhiX174 is one of the simplest viruses, having a single-stranded, closed circular DNA of 5386 nucleotide bases and four capsid proteins, J, F, G and H. A single molecule of H protein is found on each of the 12 spikes on the microvirus shell of the bacteriophage. H is involved in the ejection of the phage DNA, and at least one copy is injected into the hosts periplasmic space along with the ssDNA viral genome [PMID: 8158636]. Part of H is thought to lie outside the shell, where it recognises lipopolysaccharide from virus-sensitive bacterial strains [PMID: 10225278]. Part of H may lie within the capsid, since mutations in H can influence the DNA ejection mechanism by affecting the DNA-protein interactions [PMID: 8433365]. H may span the capsid through the hydrophilic channels formed by G proteins [PMID: 8158636].

GO terms

Biological Process

GO:0046718 viral entry into host cell

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.