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19  structures 203  species 2  interactions 364  sequences 4  architectures

Family: Hema_HEFG (PF02710)

Summary: Hemagglutinin domain of haemagglutinin-esterase-fusion glycoprotein

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This is the Wikipedia entry entitled "Haemagglutinin-esterase fusion glycoprotein". More...

Haemagglutinin-esterase fusion glycoprotein Edit Wikipedia article

Hemagglutinin domain of haemagglutinin-esterase-fusion glycoprotein
PDB 1flc EBI.jpg
x-ray structure of the haemagglutinin-esterase-fusion glycoprotein of influenza c virus
Identifiers
Symbol Hema_HEFG
Pfam PF02710
InterPro IPR003860
SCOP 1flc
SUPERFAMILY 1flc

In molecular biology, haemagglutinin-esterase fusion glycoprotein (HEF) is a multi-functional protein embedded in the viral envelope of several viruses, including influenza C virus, coronaviruses and toroviruses.[1][2] HEF is required for infectivity, and functions to recognise the host cell surface receptor, to fuse the viral and host cell membranes, and to destroy the receptor upon host cell infection. The haemagglutinin region of HEF is responsible for receptor recognition and membrane fusion, and bears a strong resemblance to the sialic acid-binding haemagglutinin found in influenza A and B viruses, except that it binds 9-O-acetylsialic acid. The esterase region of HEF is responsible for the destruction of the receptor, an action that is carried out by neuraminidase in influenza A and B viruses. The esterase domain is similar in structure to Streptomyces scabies esterase, and to acetylhydrolase, thioesterase I and rhamnogalacturonan acetylesterase.

The haemagglutinin-esterase glycoprotein HEF must be cleaved by the host's trypsin-like proteases to produce two peptides (HEF1 and HEF2) in order for the virus to be infectious. Once HEF is cleaved, the newly exposed N-terminal of the HEF2 peptide then acts to fuse the viral envelope to the cellular membrane of the host cell, which allows the virus to infect the host cell.

The haemagglutinin-esterase glycoprotein is a trimer, where each monomer is composed of three domains: an elongated stem active in membrane fusion, an esterase domain, and a receptor-binding domain, where the stem and receptor-binding domains together resemble influenza A virus haemagglutinin. Two of these domains are composed of non-contiguous sequence: the receptor-binding haemagglutinin domain is inserted into a surface loop of the esterase domain, and the esterase domain is inserted into a surface loop of the haemagglutinin stem.

References[edit]

  1. ^ de Groot RJ (February 2006). "Structure, function and evolution of the hemagglutinin-esterase proteins of corona- and toroviruses". Glycoconj. J. 23 (1-2): 59–72. doi:10.1007/s10719-006-5438-8. PMID 16575523. 
  2. ^ Rosenthal PB, Zhang X, Formanowski F, Fitz W, Wong CH, Meier-Ewert H, Skehel JJ, Wiley DC (November 1998). "Structure of the haemagglutinin-esterase-fusion glycoprotein of influenza C virus". Nature 396 (6706): 92–6. doi:10.1038/23974. PMID 9817207. 

This article incorporates text from the public domain Pfam and InterPro IPR003860

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This tab holds annotation information from the InterPro database.

InterPro entry IPR003860

Haemagglutinin-esterase fusion glycoprotein (HEF) is a multi-functional protein embedded in the viral envelope of several viruses, including influenza C virus, coronaviruses and toroviruses [PUBMED:16575523, PUBMED:9817207]. HEF is required for infectivity, and functions to recognise the host cell surface receptor, to fuse the viral and host cell membranes, and to destroy the receptor upon host cell infection. The haemagglutinin region of HEF is responsible for receptor recognition and membrane fusion, and bears a strong resemblance to the sialic acid-binding haemagglutinin found in influenza A and B viruses, except that it binds 9-O-acetylsialic acid. The esterase region of HEF is responsible for the destruction of the receptor, an action that is carried out by neuraminidase in influenza A and B viruses. The esterase domain is similar in structure to Streptomyces scabies esterase, and to acetylhydrolase, thioesterase I and rhamnogalacturonan acetylesterase.

The haemagglutinin-esterase glycoprotein HEF must be cleaved by the host's trypsin-like proteases to produce two peptides (HEF1 and HEF2) in order for the virus to be infectious. Once HEF is cleaved, the newly exposed N-terminal of the HEF2 peptide then acts to fuse the viral envelope to the cellular membrane of the host cell, which allows the virus to infect the host cell.

The haemagglutinin-esterase glycoprotein is a trimer, where each monomer is composed of three domains: an elongated stem active in membrane fusion, an esterase domain, and a receptor-binding domain, where the stem and receptor-binding domains together resemble influenza A virus haemagglutinin. Two of these domains are composed of non-contiguous sequence: the receptor-binding haemagglutinin domain is inserted into a surface loop of the esterase domain, and the esterase domain is inserted into a surface loop of the haemagglutinin stem.

This entry represents the receptor-binding haemagglutinin domain of the haemagglutinin-esterase glycoprotein.

More information on haemagglutinin proteins can be found at Protein of the Month: Bird Flu, Haemagglutinin [PUBMED:].

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Domain organisation

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  Seed
(12)
Full
(364)
Representative proteomes NCBI
(284)
Meta
(0)
RP15
(0)
RP35
(0)
RP55
(0)
RP75
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Seed source: Pfam-B_505 (release 5.5)
Previous IDs: none
Type: Family
Author: Finn RD, Bashton M, Bateman A
Number in seed: 12
Number in full: 364
Average length of the domain: 131.10 aa
Average identity of full alignment: 47 %
Average coverage of the sequence by the domain: 29.16 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 25.0 25.0
Trusted cut-off 36.9 36.9
Noise cut-off 19.3 18.9
Model length: 144
Family (HMM) version: 9
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Interactions

There are 2 interactions for this family. More...

Hema_esterase Hema_HEFG

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Hema_HEFG domain has been found. There are 19 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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