PROSITE documentation PDOC51988
Herpesviridae UL32 packaging protein family profile


Herpesviruses are large, double-stranded DNA viruses with complex virion assembly and maturation strategies. Herpesviral DNA packaging into nascent capsids requires multiple conserved viral proteins that coordinate genome encapsidation. Proteins of the UL32 family, required for viral DNA encapsidation, form homopentameric rings with a positively charged central channel that binds double-stranded DNA. The central channel of ORF68 is lined with positively charged residues that are necessary for nucleic acid binding and production of infectious virions [1,2].

Each monomer contains three zinc fingers and several bundles of α-helices connected by loops (see <PDB:6XF9>). UL32 contains several motifs with highly conserved cysteines and histidines that form three zinc fingers. The residues that compose the first two zinc fingers are perfectly conserved in all identified homologs of UL32. The third zinc finger is generally conserved in α-and γ-herpesviruses, but is missing in the β-herpesviruses. This third zinc finger is also atypical in that two coordinating residues are adjacent to each other [2].

Some proteins belonging to the UL32 packaging protein family are listed below:

  • Herpes simplex virus type 1 (HSV-1) UL32 protein [3].
  • Human cytomegalovirus (HCMV) UL52 protein [5].
  • Kaposi's sarcoma-associated virus (KSHV) ORF68 protein [1,2].
  • Epstein-Barr virus (EBV) BFLF1 protein [2].
  • Pseudorabies virus (PrV) UL32 protein [4].

The profile we developed covers the entire Herpesviridae UL32 packaging protein family.

Last update:

October 2021 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

HERPESVIRUS_UL32, PS51988; Herpesviridae UL32 packaging protein family profile  (MATRIX)


1AuthorsGardner M.R. Glaunsinger B.A.
TitleKaposi's Sarcoma-Associated Herpesvirus ORF68 Is a DNA Binding Protein Required for Viral Genome Cleavage and Packaging.
SourceJ. Virol. 92:0-0(2018).
PubMed ID29875246

2AuthorsDidychuk A.L. Gates S.N. Gardner M.R. Strong L.M. Martin A. Glaunsinger B.A.
TitleA pentameric protein ring with novel architecture is required for herpesviral packaging.
SourceElife 10:0-0(2021).
PubMed ID33554858

3AuthorsHeming J.D. Conway J.F. Homa F.L.
TitleHerpesvirus Capsid Assembly and DNA Packaging.
SourceAdv. Anat. Embryol. Cell. Biol. 223:119-142(2017).
PubMed ID28528442

4AuthorsFuchs W. Klupp B.G. Granzow H. Leege T. Mettenleiter T.C.
TitleCharacterization of pseudorabies virus (PrV) cleavage-encapsidation proteins and functional complementation of PrV pUL32 by the homologous protein of herpes simplex virus type 1.
SourceJ. Virol. 83:3930-3943(2009).
PubMed ID19193798

5AuthorsMuller C. Alain S. Gourin C. Baumert T.F. Ligat G. Hantz S.
TitleNew Insights into Human Cytomegalovirus pUL52 Structure.
SourceViruses 13:0-0(2021).
PubMed ID34452502

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