<p>An evidence describes the source of an annotation, e.g. an experiment that has been published in the scientific literature, an orthologous protein, a record from another database, etc.</p>
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<p>The annotation score provides a heuristic measure of the annotation content of a UniProtKB entry or proteome. This score <strong>cannot</strong> be used as a measure of the accuracy of the annotation as we cannot define the 'correct annotation' for any given protein.<p><a href='/help/annotation_score' target='_top'>More...</a></p>-Protein inferred from homologyi
<p>This indicates the type of evidence that supports the existence of the protein. Note that the 'protein existence' evidence does not give information on the accuracy or correctness of the sequence(s) displayed.<p><a href='/help/protein_existence' target='_top'>More...</a></p>
Select a section on the left to see content.
<p>This section provides any useful information about the protein, mostly biological knowledge.<p><a href='/help/function_section' target='_top'>More...</a></p>Functioni
The surface protein gp120 (SU) attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. This peculiar 2 stage receptor-interaction strategy allows gp120 to maintain the highly conserved coreceptor-binding site in a cryptic conformation, protected from neutralizing antibodies. Since CD4 also displays a binding site for the disulfide-isomerase P4HB/PDI, a P4HB/PDI-CD4-CXCR4-gp120 complex may form. In that complex, P4HB/PDI could reach and reduce gp120 disulfide bonds, causing major conformational changes in gp120. TXN, another PDI family member could also be involved in disulfide rearrangements in Env during fusion. These changes are transmitted to the transmembrane protein gp41 and are thought to activate its fusogenic potential by unmasking its fusion peptide (By similarity).By similarity
The surface protein gp120 is a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. DCs are professional antigen presenting cells, critical for host immunity by inducing specific immune responses against a broad variety of pathogens. They act as sentinels in various tissues where they take up antigen, process it, and present it to T-cells following migration to lymphoid organs. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected in non-lysosomal acidic organelles within the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4+ T-cells. Virion capture also seems to lead to MHC-II-restricted viral antigen presentation, and probably to the activation of HIV-specific CD4+ cells (By similarity).By similarity
The transmembrane protein gp41 (TM) acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During fusion of viral and target intracellular membranes, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Complete fusion occurs in host cell endosomes and is dynamin-dependent, however some lipid transfer might occur at the plasma membrane. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm (By similarity).By similarity
The envelope glycoprotein gp160 precursor down-modulates cell surface CD4 antigen by interacting with it in the endoplasmic reticulum and blocking its transport to the cell surface.By similarity
The gp120-gp41 heterodimer seems to contribute to T-cell depletion during HIV-1 infection. The envelope glycoproteins expressed on the surface of infected cells induce apoptosis through an interaction with uninfected cells expressing the receptor (CD4) and the coreceptors CXCR4 or CCR5. This type of bystander killing may be obtained by at least three distinct mechanisms. First, the interaction between the 2 cells can induce cellular fusion followed by nuclear fusion within the syncytium. Syncytia are condemned to die from apoptosis. Second, the 2 interacting cells may not fuse entirely and simply exchange plasma membrane lipids, after a sort of hemifusion process, followed by rapid death. Third, it is possible that virus-infected cells, on the point of undergoing apoptosis, fuse with CD4-expressing cells, in which case apoptosis is rapidly transmitted from one cell to the other and thus occurs in a sort of contagious fashion (By similarity).By similarity
The gp120-gp41 heterodimer allows rapid transcytosis of the virus through CD4 negative cells such as simple epithelial monolayers of the intestinal, rectal and endocervical epithelial barriers. Both gp120 and gp41 specifically recognize glycosphingolipids galactosyl-ceramide (GalCer) or 3' sulfo-galactosyl-ceramide (GalS) present in the lipid rafts structures of epithelial cells. Binding to these alternative receptors allows the rapid transcytosis of the virus through the epithelial cells. This transcytotic vesicle-mediated transport of virions from the apical side to the basolateral side of the epithelial cells does not involve infection of the cells themselves (By similarity).By similarity
Miscellaneous
Some HIV-2 isolates have been described that can infect cells independently of CD4, using CXCR4 as primary receptor. These isolates may have an exposed coreceptor binding site.
This isolate is from a German AIDS patient (with predominantly neurological complications) who was probably infected in Mali.
<p>The <a href="http://www.geneontology.org/">Gene Ontology (GO)</a> project provides a set of hierarchical controlled vocabulary split into 3 categories:<p><a href='/help/gene_ontology' target='_top'>More...</a></p>GO - Molecular functioni
<p>UniProtKB Keywords constitute a <a href="http://www.uniprot.org/keywords">controlled vocabulary</a> with a hierarchical structure. Keywords summarise the content of a UniProtKB entry and facilitate the search for proteins of interest.<p><a href='/help/keywords' target='_top'>More...</a></p>Keywordsi
<p>This section provides information about the protein and gene name(s) and synonym(s) and about the organism that is the source of the protein sequence.<p><a href='/help/names_and_taxonomy_section' target='_top'>More...</a></p>Names & Taxonomyi
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section provides an exhaustive list of all names of the protein, from commonly used to obsolete, to allow unambiguous identification of a protein.<p><a href='/help/protein_names' target='_top'>More...</a></p>Protein namesi
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section indicates the name(s) of the gene(s) that code for the protein sequence(s) described in the entry. Four distinct tokens exist: 'Name', 'Synonyms', 'Ordered locus names' and 'ORF names'.<p><a href='/help/gene_name' target='_top'>More...</a></p>Gene namesi
Name:env
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section provides information on the name(s) of the organism that is the source of the protein sequence.<p><a href='/help/organism-name' target='_top'>More...</a></p>Organismi
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section shows the unique identifier assigned by the NCBI to the source organism of the protein. This is known as the 'taxonomic identifier' or 'taxid'.<p><a href='/help/taxonomic_identifier' target='_top'>More...</a></p>Taxonomic identifieri
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section contains the taxonomic hierarchical classification lineage of the source organism. It lists the nodes as they appear top-down in the taxonomic tree, with the more general grouping listed first.<p><a href='/help/taxonomic_lineage' target='_top'>More...</a></p>Taxonomic lineagei
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section only exists in viral entries and indicates the host(s) either as a specific organism or taxonomic group of organisms that are susceptible to be infected by a virus.<p><a href='/help/virus_host' target='_top'>More...</a></p>Virus hosti
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section is present for entries that are part of a <a href="http://www.uniprot.org/proteomes">proteome</a>, i.e. of a set of proteins thought to be expressed by organisms whose genomes have been completely sequenced.<p><a href='/help/proteomes_manual' target='_top'>More...</a></p>Proteomesi
UP000002242
<p>A UniProt <a href="http://www.uniprot.org/manual/proteomes%5Fmanual">proteome</a> can consist of several components.<br></br>The component name refers to the genomic component encoding a set of proteins.<p><a href='/help/proteome_component' target='_top'>More...</a></p> Componenti: Genome
<p>This section provides information on the location and the topology of the mature protein in the cell.<p><a href='/help/subcellular_location_section' target='_top'>More...</a></p>Subcellular locationi
Note:It is probably concentrated at the site of budding and incorporated into the virions possibly by contacts between the cytoplasmic tail of Env and the N-terminus of Gag.By similarity
Note:The surface protein is not anchored to the viral envelope, but associates with the extravirion surface through its binding to TM. It is probably concentrated at the site of budding and incorporated into the virions possibly by contacts between the cytoplasmic tail of Env and the N-terminus of Gag (By similarity).By similarity
Topology
Feature key
Position(s)
DescriptionActions
Graphical view
Length
<p>This subsection of the <a href="http://www.uniprot.org/help/subcellular%5Flocation%5Fsection">'Subcellular location'</a> section describes the subcellular compartment where each non-membrane region of a membrane-spanning protein is found.<p><a href='/help/topo_dom' target='_top'>More...</a></p>Topological domaini
<p>This subsection of the <a href="http://www.uniprot.org/help/subcellular%5Flocation%5Fsection">'Subcellular location'</a> section describes the extent of a membrane-spanning region of the protein. It denotes the presence of both alpha-helical transmembrane regions and the membrane spanning regions of beta-barrel transmembrane proteins.<p><a href='/help/transmem' target='_top'>More...</a></p>Transmembranei
<p>This section provides information on the disease(s) and phenotype(s) associated with a protein.<p><a href='/help/pathology_and_biotech_section' target='_top'>More...</a></p>Pathology & Biotechi
<p>This subsection of the 'PTM / Processing' section denotes the presence of an N-terminal signal peptide.<p><a href='/help/signal' target='_top'>More...</a></p>Signal peptidei
<p>This subsection of the 'PTM / Processing' section describes the extent of a polypeptide chain in the mature protein following processing or proteolytic cleavage.<p><a href='/help/chain' target='_top'>More...</a></p>ChainiPRO_0000239496
<p>This subsection of the <a href="http://www.uniprot.org/help/ptm%5Fprocessing%5Fsection">PTM / Processing</a> section specifies the position and type of each covalently attached glycan group (mono-, di-, or polysaccharide).<p><a href='/help/carbohyd' target='_top'>More...</a></p>Glycosylationi
N-linked (GlcNAc...) asparagine; by hostSequence analysis
1
<p>This subsection of the PTM / Processing":/help/ptm_processing_section section describes the positions of cysteine residues participating in disulfide bonds.<p><a href='/help/disulfid' target='_top'>More...</a></p>Disulfide bondi
N-linked (GlcNAc...) asparagine; by hostSequence analysis
1
<p>This subsection of the <a href="http://www.uniprot.org/help/ptm%5Fprocessing%5Fsection">PTM / Processing</a> section specifies the position(s) and the type of covalently attached lipid group(s).<p><a href='/help/lipid' target='_top'>More...</a></p>Lipidationi
<p>This subsection of the <a href="http://www.uniprot.org/help/ptm%5Fprocessing%5Fsection">PTM/processing</a> section describes post-translational modifications (PTMs). This subsection <strong>complements</strong> the information provided at the sequence level or describes modifications for which <strong>position-specific data is not yet available</strong>.<p><a href='/help/post-translational_modification' target='_top'>More...</a></p>Post-translational modificationi
Specific enzymatic cleavages in vivo yield mature proteins. Envelope glycoproteins are synthesized as an inactive precursor that is heavily N-glycosylated and processed likely by host cell furin in the Golgi to yield the mature SU and TM proteins. The cleavage site between SU and TM requires the minimal sequence [KR]-X-[KR]-R (By similarity).By similarity
Palmitoylation of the transmembrane protein and of Env polyprotein (prior to its proteolytic cleavage) is essential for their association with host cell membrane lipid rafts. Palmitoylation is therefore required for envelope trafficking to classical lipid rafts, but not for viral replication (By similarity).By similarity
Sites
Feature key
Position(s)
DescriptionActions
Graphical view
Length
<p>This subsection describes interesting single amino acid sites on the sequence that are not defined in any other subsection. This subsection can be displayed in different sections ('Function', 'PTM / Processing', 'Pathology and Biotech') according to its content.<p><a href='/help/site' target='_top'>More...</a></p>Sitei
<p>This section provides information on the quaternary structure of a protein and on interaction(s) with other proteins or protein complexes.<p><a href='/help/interaction_section' target='_top'>More...</a></p>Interactioni
<p>This subsection of the <a href="http://www.uniprot.org/help/interaction%5Fsection">'Interaction'</a> section provides information about the protein quaternary structure and interaction(s) with other proteins or protein complexes (with the exception of physiological receptor-ligand interactions which are annotated in the <a href="http://www.uniprot.org/help/function%5Fsection">'Function'</a> section).<p><a href='/help/subunit_structure' target='_top'>More...</a></p>Subunit structurei
The mature envelope protein (Env) consists of a homotrimer of non-covalently associated gp120-gp41 heterodimers. The resulting complex protrudes from the virus surface as a spike. There seems to be as few as 10 spikes on the average virion.
Interacts with human CD4, CCR5 and CXCR4, to form a P4HB/PDI-CD4-CXCR4-gp120 complex. Gp120 also interacts with the C-type lectins CD209/DC-SIGN and CLEC4M/DC-SIGNR (collectively referred to as DC-SIGN(R)). Gp120 and gp41 interact with GalCer (By similarity).
The mature envelope protein (Env) consists of a homotrimer of non-covalently associated gp120-gp41 heterodimers. The resulting complex protrudes from the virus surface as a spike. There seems to be as few as 10 spikes on the average virion.
By similarity
Protein-protein interaction databases
The Biological General Repository for Interaction Datasets (BioGRID)
<p>This section provides information on sequence similarities with other proteins and the domain(s) present in a protein.<p><a href='/help/family_and_domains_section' target='_top'>More...</a></p>Family & Domainsi
Region
Feature key
Position(s)
DescriptionActions
Graphical view
Length
<p>This subsection of the 'Family and Domains' section describes a region of interest that cannot be described in other subsections.<p><a href='/help/region' target='_top'>More...</a></p>Regioni
<p>This subsection of the 'Family and domains' section denotes the positions of regions of coiled coil within the protein.<p><a href='/help/coiled' target='_top'>More...</a></p>Coiled coili
<p>This subsection of the 'Family and Domains' section describes a short (usually not more than 20 amino acids) conserved sequence motif of biological significance.<p><a href='/help/motif' target='_top'>More...</a></p>Motifi
<p>This subsection of the 'Family and Domains' section describes the position of regions of compositional bias within the protein and the particular amino acids that are over-represented within those regions.<p><a href='/help/compbias' target='_top'>More...</a></p>Compositional biasi
<p>This subsection of the 'Family and domains' section provides general information on the biological role of a domain. The term 'domain' is intended here in its wide acceptation, it may be a structural domain, a transmembrane region or a functional domain. Several domains are described in this subsection.<p><a href='/help/domain_cc' target='_top'>More...</a></p>Domaini
Some of the most genetically diverse regions of the viral genome are present in Env. They are called variable regions 1 through 5 (V1 through V5). Coreceptor usage of gp120 is determined mainly by the primary structure of the third variable region (V3) in the outer domain of gp120. Binding to CCR5 involves a region adjacent in addition to V3 (By similarity).By similarity
The 17 amino acids long immunosuppressive region is present in many retroviral envelope proteins. Synthetic peptides derived from this relatively conserved sequence inhibit immune function in vitro and in vivo (By similarity).By similarity
<p>This section displays by default the canonical protein sequence and upon request all isoforms described in the entry. It also includes information pertinent to the sequence(s), including <a href="http://www.uniprot.org/help/sequence%5Flength">length</a> and <a href="http://www.uniprot.org/help/sequences">molecular weight</a>. The information is filed in different subsections. The current subsections and their content are listed below:<p><a href='/help/sequences_section' target='_top'>More...</a></p>Sequencei
<p>This subsection of the <a href="http://www.uniprot.org/help/sequences%5Fsection">Sequence</a> section indicates if the <a href="http://www.uniprot.org/help/canonical%5Fand%5Fisoforms">canonical sequence</a> displayed by default in the entry is complete or not.<p><a href='/help/sequence_status' target='_top'>More...</a></p>Sequence statusi: Complete.
<p>This subsection of the <a href="http://www.uniprot.org/help/sequences%5Fsection">Sequence</a> section indicates if the <a href="http://www.uniprot.org/help/canonical%5Fand%5Fisoforms">canonical sequence</a> displayed by default in the entry is in its mature form or if it represents the precursor.<p><a href='/help/sequence_processing' target='_top'>More...</a></p>Sequence processingi: The displayed sequence is further processed into a mature form.
<p>The checksum is a form of redundancy check that is calculated
from the sequence. It is useful for tracking sequence updates.</p>
<p>It should be noted that while, in theory, two different sequences could
have the same checksum value, the likelihood that this would happen
is extremely low.</p>
<p>However UniProtKB may contain entries with identical sequences in case
of multiple genes (paralogs).</p>
<p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64)
using the generator polynomial: x<sup>64</sup> + x<sup>4</sup> + x<sup>3</sup> + x + 1.
The algorithm is described in the ISO 3309 standard.
</p>
<p class="publication">Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.<br />
<strong>Cyclic redundancy and other checksums</strong><br />
<a href="http://www.nrbook.com/b/bookcpdf.php">Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993)</a>)</p>
Checksum:iC7D24EE10136FEDC
<p>This section provides links to proteins that are similar to the protein sequence(s) described in this entry at different levels of sequence identity thresholds (100%, 90% and 50%) based on their membership in UniProt Reference Clusters (<a href="http://www.uniprot.org/help/uniref">UniRef</a>).<p><a href='/help/similar_proteins_section' target='_top'>More...</a></p>Similar proteinsi
<p>This section is used to point to information related to entries and found in data collections other than UniProtKB.<p><a href='/help/cross_references_section' target='_top'>More...</a></p>Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi
<p>This section provides general information on the entry.<p><a href='/help/entry_information_section' target='_top'>More...</a></p>Entry informationi
<p>This subsection of the 'Entry information' section provides a mnemonic identifier for a UniProtKB entry, but it is not a stable identifier. Each reviewed entry is assigned a unique entry name upon integration into UniProtKB/Swiss-Prot.<p><a href='/help/entry_name' target='_top'>More...</a></p>Entry namei
ENV_HV2BE
<p>This subsection of the 'Entry information' section provides one or more accession number(s). These are stable identifiers and should be used to cite UniProtKB entries. Upon integration into UniProtKB, each entry is assigned a unique accession number, which is called 'Primary (citable) accession number'.<p><a href='/help/accession_numbers' target='_top'>More...</a></p>Accessioni
<p>This subsection of the 'Entry information' section shows the date of integration of the entry into UniProtKB, the date of the last sequence update and the date of the last annotation modification ('Last modified'). The version number for both the entry and the <a href="http://www.uniprot.org/help/canonical%5Fand%5Fisoforms">canonical sequence</a> are also displayed.<p><a href='/help/entry_history' target='_top'>More...</a></p>Entry historyi
Integrated into UniProtKB/Swiss-Prot:
November 1, 1990
Last sequence update:
November 1, 1990
Last modified:
April 7, 2021
This is version 123 of the entry and version 1 of the sequence. See complete history.
<p>This subsection of the 'Entry information' section indicates whether the entry has been manually annotated and reviewed by UniProtKB curators or not, in other words, if the entry belongs to the Swiss-Prot section of UniProtKB (<strong>reviewed</strong>) or to the computer-annotated TrEMBL section (<strong>unreviewed</strong>).<p><a href='/help/entry_status' target='_top'>More...</a></p>Entry statusi
<p>This section contains any relevant information that doesn't fit in any other defined sections<p><a href='/help/miscellaneous_section' target='_top'>More...</a></p>Miscellaneousi
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