O00370 · LORF2_HUMAN
- ProteinLINE-1 retrotransposable element ORF2 protein
- StatusUniProtKB reviewed (Swiss-Prot)
- Organism
- Amino acids1275 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Has reverse transcriptase activity required for target-primed reverse transcription of the LINE-1 element mRNA, a crucial step in LINE-1 retrotransposition (PubMed:7516468, PubMed:9140393).
Also has endonuclease activity that allows the introduction of nicks in the chromosomal target DNA (PubMed:17626046, PubMed:34554261, PubMed:8945517).
Cleaves DNA in AT-rich regions between a 5' stretch of purines and a 3' stretch of pyrimidines, corresponding to sites of LINE-1 integration in the genome (PubMed:8945517).
Conformational properties of the target DNA sequence rather than specific nucleotides are key determinants of the ORF2p capacity for sequence-specific DNA recognition (PubMed:17626046, PubMed:34554261).
Unlike related endonucleases, does not bend the DNA helix but causes compression near the cleavage site (PubMed:34554261).
Also has endonuclease activity that allows the introduction of nicks in the chromosomal target DNA (PubMed:17626046, PubMed:34554261, PubMed:8945517).
Cleaves DNA in AT-rich regions between a 5' stretch of purines and a 3' stretch of pyrimidines, corresponding to sites of LINE-1 integration in the genome (PubMed:8945517).
Conformational properties of the target DNA sequence rather than specific nucleotides are key determinants of the ORF2p capacity for sequence-specific DNA recognition (PubMed:17626046, PubMed:34554261).
Unlike related endonucleases, does not bend the DNA helix but causes compression near the cleavage site (PubMed:34554261).
Miscellaneous
Long interspersed element-1/LINE-1/L1 retrotransposons are present in more than 500'000 full (6 kb) or truncated copies in the human genome. Most of them are inactive but one estimate is that 80 to 100 of those elements could be transcribed, translated and active in any individual. An active LINE-1 encodes for 2 proteins translated from a single RNA containing two non-overlapping ORFs, ORF1 and ORF2. ORF2p is described in this entry as a representative of all ORF2p potentially expressed by active elements. ORF1p is described in the related entry AC Q9UN81.
Insertions of LINE-1 (L1) retrotransposons can occur frequently at CRISPR/Cas9 editing sites. The reverse transcriptase activity of ORF2p mediates L1 insertions into CRISPR/Cas9-initiated double-strand breaks (DSB). De novo L1 insertions are rare during genome editing by prime editors and by cytidine or adenine base editors, consistent with their reduced DSB formation.
Catalytic activity
- a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1)
Features
Showing features for binding site, active site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 43 | Mg2+ 1 (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Active site | 115 | |||||
Sequence: Y | ||||||
Active site | 145 | Proton donor/acceptor | ||||
Sequence: D | ||||||
Binding site | 600 | Mg2+ 2 (UniProtKB | ChEBI); catalytic | ||||
Sequence: D | ||||||
Binding site | 702 | Mg2+ 2 (UniProtKB | ChEBI); catalytic | ||||
Sequence: D | ||||||
Binding site | 703 | Mg2+ 2 (UniProtKB | ChEBI); catalytic | ||||
Sequence: D |
GO annotations
Aspect | Term | |
---|---|---|
Molecular Function | metal ion binding | |
Molecular Function | RNA binding | |
Molecular Function | RNA-directed DNA polymerase activity | |
Molecular Function | type II site-specific deoxyribonuclease activity | |
Biological Process | DNA recombination | |
Biological Process | nucleic acid metabolic process | |
Biological Process | retrotransposition |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameLINE-1 retrotransposable element ORF2 protein
- Short namesORF2p
Including 2 domains:
- Recommended nameReverse transcriptase
- EC number
- Recommended nameEndonuclease
- EC number
Organism names
- Organism
- Taxonomic lineageEukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Primates > Haplorrhini > Catarrhini > Hominidae > Homo
Accessions
- Primary accessionO00370
Proteomes
Organism-specific databases
Disease & Variants
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 14 | Loss of endonuclease activity and reduced transposition efficiency. | ||||
Sequence: N → A | ||||||
Mutagenesis | 43 | Loss of endonuclease activity. | ||||
Sequence: E → A | ||||||
Mutagenesis | 145 | Loss of endonuclease activity and reduced transposition efficiency. Reduced transposition efficiency; when associated with A-147. | ||||
Sequence: D → A | ||||||
Mutagenesis | 147 | Reduced transposition efficiency; when associated with A-145. | ||||
Sequence: N → A | ||||||
Mutagenesis | 155 | Reduced DNA nicking activity and reduced transposition efficiency. | ||||
Sequence: R → A | ||||||
Mutagenesis | 192 | Reduced transposition efficiency. | ||||
Sequence: T → V | ||||||
Mutagenesis | 202 | Reduced DNA nicking activity and reduced transposition efficiency. | ||||
Sequence: S → A | ||||||
Mutagenesis | 204 | Reduced DNA nicking activity and reduced transposition efficiency. | ||||
Sequence: I → Y | ||||||
Mutagenesis | 205 | Loss of endonuclease activity and reduced transposition efficiency. | ||||
Sequence: D → G | ||||||
Mutagenesis | 226 | Increased endonuclease activity. | ||||
Sequence: Y → K | ||||||
Mutagenesis | 230 | Loss of endonuclease activity and reduced transposition efficiency. | ||||
Sequence: H → A | ||||||
Mutagenesis | 703 | Reduced transposition efficiency. | ||||
Sequence: D → Y | ||||||
Mutagenesis | 1130 | No effect on binding to RNA; when associated with R-1134, R-1143 and R-1147. | ||||
Sequence: C → R | ||||||
Mutagenesis | 1134 | No effect on binding to RNA; when associated with R-1130, R-1143 and R-1147. | ||||
Sequence: C → R | ||||||
Mutagenesis | 1143 | No effect on binding to RNA; when associated with R-1130, R-1134 and R-1147. | ||||
Sequence: C → R | ||||||
Mutagenesis | 1147 | No effect on binding to RNA; when associated with R-1130, R-1134 and R-1143. | ||||
Sequence: C → R |
Miscellaneous
Genetic variation databases
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000425082 | 1-1275 | LINE-1 retrotransposable element ORF2 protein | |||
Sequence: MTGSNSHITILTLNVNGLNSPIKRHRLASWIKSQDPSVCCIQETHLTCRDTHRLKIKGWRKIYQANGKQKKAGVAILVSDKTDFKPTKIKRDKEGHYIMVKGSIQQEELTILNIYAPNTGAPRFIKQVLSDLQRDLDSHTLIMGDFNTPLSILDRSTRQKVNKDTQELNSALHQTDLIDIYRTLHPKSTEYTFFSAPHHTYSKIDHIVGSKALLSKCKRTEIITNYLSDHSAIKLELRIKNLTQSRSTTWKLNNLLLNDYWVHNEMKAEIKMFFETNENKDTTYQNLWDAFKAVCRGKFIALNAYKRKQERSKIDTLTSQLKELEKQEQTHSKASRRQEITKIRAELKEIETQKTLQKINESRSWFFERINKIDRPLARLIKKKREKNQIDTIKNDKGDITTDPTEIQTTIREYYKHLYANKLENLEEMDTFLDTYTLPRLNQEEVESLNRPITGSEIVAIINSLPTKKSPGPDGFTAEFYQRYKEELVPFLLKLFQSIEKEGILPNSFYEASIILIPKPGRDTTKKENFRPISLMNIDAKILNKILANRIQQHIKKLIHHDQVGFIPGMQGWFNIRKSINVIQHINRAKDKNHVIISIDAEKAFDKIQQPFMLKTLNKLGIDGMYLKIIRAIYDKPTANIILNGQKLEAFPLKTGTRQGCPLSPLLFNIVLEVLARAIRQEKEIKGIQLGKEEVKLSLFADDMIVYLENPIVSAQNLLKLISNFSKVSGYKINVQKSQAFLYNNNRQTESQIMGELPFTIASKRIKYLGIQLTRDVKDLFKENYKPLLKEIKEDTNKWKNIPCSWVGRINIVKMAILPKVIYRFNAIPIKLPMTFFTELEKTTLKFIWNQKRARIAKSILSQKNKAGGITLPDFKLYYKATVTKTAWYWYQNRDIDQWNRTEPSEIMPHIYNYLIFDKPEKNKQWGKDSLLNKWCWENWLAICRKLKLDPFLTPYTKINSRWIKDLNVKPKTIKTLEENLGITIQDIGVGKDFMSKTPKAMATKDKIDKWDLIKLKSFCTAKETTIRVNRQPTTWEKIFATYSSDKGLISRIYNELKQIYKKKTNNPIKKWAKDMNRHFSKEDIYAAKKHMKKCSSSLAIREMQIKTTMRYHLTPVRMAIIKKSGNNRCWRGCGEIGTLVHCWWDCKLVQPLWKSVWRFLRDLELEIPFDPAIPLLGIYPKDYKSCCYKDTCTRMFIAALFTIAKTWNQPNCPTMIDWIKKMWHIYTMEYYAAIKNDEFISFVGTWMKLETIILSKLSQEQKTKHRIFSLIGGN |
Proteomic databases
PTM databases
Structure
Family & Domains
Features
Showing features for region, domain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Region | 1-239 | Endonuclease activity | ||||
Sequence: MTGSNSHITILTLNVNGLNSPIKRHRLASWIKSQDPSVCCIQETHLTCRDTHRLKIKGWRKIYQANGKQKKAGVAILVSDKTDFKPTKIKRDKEGHYIMVKGSIQQEELTILNIYAPNTGAPRFIKQVLSDLQRDLDSHTLIMGDFNTPLSILDRSTRQKVNKDTQELNSALHQTDLIDIYRTLHPKSTEYTFFSAPHHTYSKIDHIVGSKALLSKCKRTEIITNYLSDHSAIKLELRI | ||||||
Domain | 498-773 | Reverse transcriptase | ||||
Sequence: SIEKEGILPNSFYEASIILIPKPGRDTTKKENFRPISLMNIDAKILNKILANRIQQHIKKLIHHDQVGFIPGMQGWFNIRKSINVIQHINRAKDKNHVIISIDAEKAFDKIQQPFMLKTLNKLGIDGMYLKIIRAIYDKPTANIILNGQKLEAFPLKTGTRQGCPLSPLLFNIVLEVLARAIRQEKEIKGIQLGKEEVKLSLFADDMIVYLENPIVSAQNLLKLISNFSKVSGYKINVQKSQAFLYNNNRQTESQIMGELPFTIASKRIKYLGIQL | ||||||
Region | 1096-1275 | Carboxy-terminal segment; binds RNA | ||||
Sequence: SSSLAIREMQIKTTMRYHLTPVRMAIIKKSGNNRCWRGCGEIGTLVHCWWDCKLVQPLWKSVWRFLRDLELEIPFDPAIPLLGIYPKDYKSCCYKDTCTRMFIAALFTIAKTWNQPNCPTMIDWIKKMWHIYTMEYYAAIKNDEFISFVGTWMKLETIILSKLSQEQKTKHRIFSLIGGN | ||||||
Domain | 1242-1260 | DUF1725 | ||||
Sequence: SFVGTWMKLETIILSKLSQ |
Domain
The C-terminal segment (CTS) binds to RNA with high affinity in the nanomolar range but without apparent sequence specificity.
The size and flexibility of the betaB6-betaB5 hairpin loop at residues 191-205 are crucial for activity. Variation of the loop sequence results in an altered DNA nicking profile including novel sites.
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length1,275
- Mass (Da)149,012
- Last updated1997-07-01 v1
- Checksum588703688E7129FF
Keywords
- Technical term