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annotation rule: PRU00405

General rule information [?]

Accession PRU00405
Dates 28-FEB-2005 (Created)
27-OCT-2018 (Last updated, Version 18)
Data class Domain
Predictors PROSITE; PS50878; RT_POL
Name Reverse transcriptase (RT) catalytic domain
Function The RT domain exhibits two enzymatic activities: RNA-dependent DNA polymerase and DNA-dependent DNA polymerase.

Propagated annotation [?]


Description [?]

case <FTGroup:1>
+ RecName: EC=2.7.7.49; EC=2.7.7.7;
end case


Comments [?]

case <OS:Human immunodeficiency virus> and <Feature:PS50879>
Function RT is a multifunctional enzyme that converts the viral dimeric RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNAse H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA(3)-Lys binds to the primer-binding site (PBS) situated at the 5' end of the viral RNA. RT uses the 3' end of the tRNA primer to perfom a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthetized short ssDNA to perfom the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for two polypurine tracts (PPTs) situated at the 5' end and near the center of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPTs that have not been removed by RNase H as primers. PPTs and tRNA primers are then removed by RNAse H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends.
else case <OC:Alpharetrovirus> and <Feature:PS50879>
Function RT is a multifunctional enzyme that converts the viral dimeric RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNAse H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA-Trp binds to the primer-binding site (PBS) situated at the 5' end of the viral RNA. RT uses the 3' end of the tRNA primer to perfom a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthetized short ssDNA to perfom the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for a polypurine tract (PPT) situated at the 5' end of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPT that has not been removed by RNase H as primers. PPT and tRNA primers are then removed by RNAse H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends.
else case <OC:Betaretrovirus> or <OC:Gammaretrovirus> or <OC:Epsilonretrovirus> or <OC:Lentivirus> and <Feature:PS50879>
Function RT is a multifunctional enzyme that converts the viral dimeric RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNAse H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA binds to the primer-binding site (PBS) situated at the 5' end of the viral RNA. RT uses the 3' end of the tRNA primer to perfom a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthetized short ssDNA to perfom the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for a polypurine tract (PPT) situated at the 5' end of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPT that has not been removed by RNase H as primers. PPT and tRNA primers are then removed by RNAse H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends.
else case <OC:Deltaretrovirus> and <Feature:PS50879>
Function RT is a multifunctional enzyme that converts the viral dimeric RNA genome into dsDNA in the cytoplasm, shortly after virus entry into the cell. This enzyme displays a DNA polymerase activity that can copy either DNA or RNA templates, and a ribonuclease H (RNAse H) activity that cleaves the RNA strand of RNA-DNA heteroduplexes in a partially processive 3' to 5' endonucleasic mode. Conversion of viral genomic RNA into dsDNA requires many steps. A tRNA-Pro binds to the primer-binding site (PBS) situated at the 5' end of the viral RNA. RT uses the 3' end of the tRNA primer to perfom a short round of RNA-dependent minus-strand DNA synthesis. The reading proceeds through the U5 region and ends after the repeated (R) region which is present at both ends of viral RNA. The portion of the RNA-DNA heteroduplex is digested by the RNase H, resulting in a ssDNA product attached to the tRNA primer. This ssDNA/tRNA hybridizes with the identical R region situated at the 3' end of viral RNA. This template exchange, known as minus-strand DNA strong stop transfer, can be either intra- or intermolecular. RT uses the 3' end of this newly synthetized short ssDNA to perfom the RNA-dependent minus-strand DNA synthesis of the whole template. RNase H digests the RNA template except for a polypurine tract (PPT) situated at the 5' end of the genome. It is not clear if both polymerase and RNase H activities are simultaneous. RNase H probably can proceed both in a polymerase-dependent (RNA cut into small fragments by the same RT performing DNA synthesis) and a polymerase-independent mode (cleavage of remaining RNA fragments by free RTs). Secondly, RT performs DNA-directed plus-strand DNA synthesis using the PPT that has not been removed by RNase H as primers. PPT and tRNA primers are then removed by RNAse H. The 3' and 5' ssDNA PBS regions hybridize to form a circular dsDNA intermediate. Strand displacement synthesis by RT to the PBS and PPT ends produces a blunt ended, linear dsDNA copy of the viral genome that includes long terminal repeats (LTRs) at both ends.
end case

case <FTGroup:1>
Catalytic activity Reaction=a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1); Xref=Rhea:RHEA:22508, Rhea:RHEA- COMP:11130, Rhea:RHEA-COMP:11131, ChEBI:CHEBI:33019, ChEBI:CHEBI:61560, ChEBI:CHEBI:83828; EC=2.7.7.49;.
Reaction=a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1); Xref=Rhea:RHEA:22508, Rhea:RHEA- COMP:11130, Rhea:RHEA-COMP:11131, ChEBI:CHEBI:33019, ChEBI:CHEBI:61560, ChEBI:CHEBI:83828; EC=2.7.7.7;.
end case

case <OC:Retroviridae>
Cofactor Mg(2+)
Note: The RT polymerase active site binds 2 magnesium ions.
end case

case <OC:Lentivirus>
Subunit The reverse transcriptase is a heterodimer of p66 RT and p51 RT (RT p66/p51). Heterodimerization of RT is essential for DNA polymerase activity. Despite the sequence identities, p66 RT and p51 RT have distinct folding.
else case <OC:Alpharetrovirus>
Subunit The reverse transcriptase forms a heterodimer of alpha and beta subunits.
else case <OC:Gammaretrovirus>
Subunit The reverse transcriptase is a monomer.
end case

case <OC:Lentivirus>
Domain The p66 RT is structured in five subdomains: finger, palm, thumb, connection and RNase H. Within the palm subdomain, the "primer grip" region is thought to be involved in the positioning of the primer terminus for accomodating the incoming nucleotide. The RNase H domain stabilizes the association of RT with primer-template.
end case

case <OC:Lentivirus>
Ptm Specific enzymatic cleavages by the viral protease yield mature proteins. The protease is released by autocatalytic cleavage. The polyprotein is cleaved during and after budding, this process is termed maturation. Proteolytic cleavage of p66 RT removes the RNase H domain to yield the p51 RT subunit.
end case

case <OC:Retroviridae>
Miscellaneous The reverse transcriptase is an error-prone enzyme that lacks a proof-reading function. High mutations rate is a direct consequence of this characteristic. RT also displays frequent template swiching leading to high recombination rate. Recombination mostly occurs between homologous regions of the two copackaged RNA genomes. If these two RNA molecules derive from different viral strains, reverse transcription will give rise to highly recombinated proviral DNAs.
end case


Gene Ontology [?]

GO:0016740; Molecular function: transferase activity.
GO:0016779; Molecular function: nucleotidyltransferase activity.
GO:0003964; Molecular function: RNA-directed DNA polymerase activity.
GO:0003887; Molecular function: DNA-directed DNA polymerase activity.

Keywords [?]


Features [?]

From: PS50878
Key     From     To       Description   Tag   Condition   FTGroup
DOMAIN     from     to       Reverse transcriptase #        
METAL     66     66       Magnesium; catalytic     D   1
METAL     130     130       Magnesium; catalytic     D   1
METAL     131     131       Magnesium; catalytic     D   1

Additional information [?]

Size range 140-285 amino acids
Related rules None
Repeats 1
Topology Undefined
Example O14746 (TERT_HUMAN)
Scope
Eukaryota
Bacteria
Viruses

Copyright

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to license@isb-sib.ch or see: prosite_license.html.



UniProtKB rule member sequences [?]