HHV capsid portal protein

HHV capsid portal protein

HHV Capsid Portal Protein, or HSV-1 UL-6 protein, is the protein which forms a cylindrical portal in the capsid of Herpes simplex virus (HSV-1). The protein is commonly referred to as the "HSV-1 UL-6" protein because it is is the transcription product of Herpes gene UL-6.

The Herpes viral DNA enters and exits the capsid via the capsid portal. The capsid portal is formed by twelve copies of portal protein arranged as a ring; the proteins contain a leucine zipper sequence of amino acids which allow them to adhere to each other.] Each icosahedral capsid contains a single portal, located in one vertex. cite journal|pmid=15507654|title=Structure and polymorphism of the UL6 portal protein of herpes simplex virus type 1|author=Trus BL, Cheng N, Newcomb WW, Homa FL, Brown JC, Steven AC|journal=Journal of Virology|date=2004 Nov|volume=78|issue=22|pages=12668–71|doi=10.1128/JVI.78.22.12668-12671.2004(Article: [http://jvi.asm.org/cgi/content/full/78/22/12668?view=long&pmid=15507654] )] ]

The portal is formed during initial capsid assembly and interacts with "scaffolding proteins" that construct the procapsid.] cite journal|pmid=12941896|title=Assembly of the herpes simplex virus capsid: identification of soluble scaffold-portal complexes and their role in formation of portal-containing capsids|author=Newcomb WW, Thomsen DR, Homa FL, Brown JC|journal=Journal of Virology|date=2003 Sep|volume=77|issue=18|pages=9862–71|doi=10.1128/JVI.77.18.9862-9871.2003 (Article: [http://jvi.asm.org/cgi/content/full/77/18/9862?view=long&pmid=12941896] )] cite journal|pmid=15596809|title=Identification of a region in the herpes simplex virus scaffolding protein required for interaction with the portal|author=Singer GP, Newcomb WW, Thomsen DR, Homa FL, Brown JC|journal=Journal of Virology|date=2007 May 10. Epub 2006 Dec 22|volume=361|issue=2|pages=426–34 (Article: [http://jvi.asm.org/cgi/content/full/79/1/132?view=long&pmid=15596809] )] When the capsid is nearly complete, the viral DNA enters the capsid (i.e, the DNA is "encapsidated") by a mechanism invovling the portal and a DNA-binding protein complex similar to bacteriophage terminase. ] Multiple studies suggest an evolutionary relationship between Capsid Portal Protein and bacteriophage portal proteins.

When virus infects a cell, it is necessary for the viral DNA to be released from the capsid. The Herpes virus DNA exits through the capsid portal.cite journal|title=Uncoating the Herpes Simplex Virus Genome|author=Newcomb WW, Booy FP, Brown JC|journal=Journal of molecular biology|date=2007 May 13|pmid=17540405]

The genetic sequence of HSV-1 gene UL-6 is conserved across the Herpesviridae family and this family of genes is known as the "Herpesvirus UL6-like" gene family. [http://www.ncbi.nlm.nih.gov/Structure/cdd/cddsrv.cgi?uid=65550 Herpesvirus UL6 like Conserved Domains view at NCBI] ] "UL-6" is nomenclature meaning that the protein is genetically encoded by the sixth (6th) open reading frame found in the viral genome segment named "Unique-Long (UL)".

tudies


Dodecameric structure

Research performed in 2004 used electron microscopy to predict that UL-6 forms 11, 12, 13, and 14-unit polymers. The dodecameric (twelve-unit) form was found to be most likely.

Refinements to the electron microscopy in 2007 allowed finding that the portal is a twelve (12)-unit polymer present at one of the twelve capsid vertices instead of the UL-19 pentamer found at non-portal vertices.

Leucine zipper creates inter-protein adhesion

A study using deletion and mutation of the UL-6 amino acid sequence demonstrated the leucine residues in a predicuted leucine zipper motif were required for formation of the dodecameric ring sturcutre.

Early involvement in capsid assembly

Assembly of portal units is an initial step in constructing capsids of viral progeny. Capsids assembled in the absence of portals lack portals.

Interaction with capsid scaffolding protein

In 2003, gel eletrophoresis studies demonstrated that intact UL-6 portals associate in vitro with viral protein UL-26. This association is antagonized by that action of WAY-150138, a thiourea inhibitor of HHV encapsidation.

Further investigation during 2006 showed that assembly of capsid with portal depends on interaction of UL-6 with "scaffolding" protein UL-26.5, amino acids 143 through 151.

Interaction with terminase complex

UL-6 associates with a UL-15/UL-28 protein complex during capsid assembly. The UL-15/UL-28 is believed to bind with viral DNA and serve the same purpose as terminase by packing viral DNA into the capsid during capsid assembly.

Function during DNA egress

The DNA exits the capsid in a single linear segment. DNA exit may be controlled by UL-6 and dependent on temperature or environmental proteins.

Notes


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Nef (protein) — Negative factor, (F Protein) or Nef NMR structure of the NEF protein based on the PDB 2NEF coordinates. Identifiers Symbol …   Wikipedia

  • Viral matrix protein — Identifiers Symbol Matrix Pfam PF00661 InterPro …   Wikipedia

  • Viral nonstructural protein — In virology, a nonstructural protein is a protein encoded by a virus but it is not part of the viral particle.[1] See also NSP1 (rotavirus) NSP4 (rotavirus) NSP5 (rotavirus) NSP6 (virus) References ^ MeSH …   Wikipedia

  • Structure and genome of HIV — The genome and proteins of HIV have been the subject of extensive research since the discovery of the virus in 1983.[1][2] The discovery of the virus itself was not until two years after the first major cases of AIDS associated illnesses were… …   Wikipedia

  • Viral envelope — Schematic of a Cytomegalovirus Many viruses (e.g. influenza and many animal viruses) have viral envelopes covering their protein capsids.[1] The envelopes typically are derived from portions of the host cell membranes (pho …   Wikipedia

  • Hepatitis B virus — For the disease, see Hepatitis B. Hepatitis B virus TEM micrograph showing hepatitis B viruses Virus classification Group …   Wikipedia

  • NSP1 (rotavirus) — NSP1, the product of rotavirus gene 5, is an nonstructural RNA binding protein that contains a cysteine rich region and is a component of early replication intermediates. RNA folding predictions suggest that this region of the NSP1 mRNA can… …   Wikipedia

  • NSP2 (rotavirus) — NSP2, is a rotavirus nonstructural RNA binding protein that accumulates in cytoplasmic inclusions (viroplasms) and is required for genome replication.[1] NSP2 is closely associated in vivo with the viral replicase.[2] The non structural protein… …   Wikipedia

  • NSP6 (rotavirus) — Gene 11 of Rotavirus encodes a nonstructural protein, NSP5 and also encodes NSP6, from an out of phase open reading frame.[1] In contrast to the other rotavirus non structural proteins, NSP6 was found to have a high rate of turnover, being… …   Wikipedia

  • NS2 (HCV) — HCV genome NS2 is a viral protein found in hepatitis C.[1] References ^ …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”