ID DPOL_DHBV1 Reviewed; 836 AA. AC P03162; DT 21-JUL-1986, integrated into UniProtKB/Swiss-Prot. DT 01-OCT-1996, sequence version 2. DT 10-JUN-2026, entry version 108. DE RecName: Full=Protein P; DE Includes: DE RecName: Full=DNA-directed DNA polymerase; DE EC=2.7.7.7; DE Includes: DE RecName: Full=RNA-directed DNA polymerase; DE EC=2.7.7.49; DE Includes: DE RecName: Full=Ribonuclease H; DE EC=3.1.26.4; GN Name=P; OS Duck hepatitis B virus (strain United States/DHBV-16) (DHBV). OC Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes; OC Blubervirales; Hepadnaviridae; Avihepadnavirus; OC Avihepadnavirus anatigruidae; Duck hepatitis B virus. OX NCBI_TaxID=489543; OH NCBI_TaxID=8835; Anas (ducks). RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RX PubMed=6699938; DOI=10.1128/jvi.49.3.782-792.1984; RA Mandart E., Kay A., Galibert F.; RT "Nucleotide sequence of a cloned duck hepatitis B virus genome: comparison RT with woodchuck and human hepatitis B virus sequences."; RL J. Virol. 49:782-792(1984). RN [2] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 794-836. RX PubMed=6328037; DOI=10.1128/jvi.51.1.181-191.1984; RA Molnar-Kimber K.L., Summers J.W., Mason W.S.; RT "Mapping of the cohesive overlap of duck hepatitis B virus DNA and of the RT site of initiation of reverse transcription."; RL J. Virol. 51:181-191(1984). RN [3] RP ACTIVATION BY HOST HSC70 AND HSP40. RX PubMed=12851401; DOI=10.1074/jbc.m301069200; RA Beck J., Nassal M.; RT "Efficient Hsp90-independent in vitro activation by Hsc70 and Hsp40 of duck RT hepatitis B virus reverse transcriptase, an assumed Hsp90 client protein."; RL J. Biol. Chem. 278:36128-36138(2003). RN [4] RP ACTIVATION BY HOST CHAPERONES. RX PubMed=17913810; DOI=10.1128/jvi.01196-07; RA Stahl M., Beck J., Nassal M.; RT "Chaperones activate hepadnavirus reverse transcriptase by transiently RT exposing a C-proximal region in the terminal protein domain that RT contributes to epsilon RNA binding."; RL J. Virol. 81:13354-13364(2007). RN [5] RP REVIEW. RX PubMed=17206754; DOI=10.3748/wjg.v13.i1.48; RA Beck J., Nassal M.; RT "Hepatitis B virus replication."; RL World J. Gastroenterol. 13:48-64(2007). CC -!- FUNCTION: Multifunctional enzyme that converts the viral RNA genome CC into dsDNA in viral cytoplasmic capsids. This enzyme displays a DNA CC polymerase activity that can copy either DNA or RNA templates, and a CC ribonuclease H (RNase H) activity that cleaves the RNA strand of RNA- CC DNA heteroduplexes in a partially processive 3'- to 5'-endonucleasic CC mode. Neo-synthesized pregenomic RNA (pgRNA) are encapsidated together CC with the P protein, and reverse-transcribed inside the nucleocapsid. CC Initiation of reverse-transcription occurs first by binding the epsilon CC loop on the pgRNA genome, and is initiated by protein priming, thereby CC the 5'-end of (-)DNA is covalently linked to P protein. Partial (+)DNA CC is synthesized from the (-)DNA template and generates the relaxed CC circular DNA (RC-DNA) genome. After budding and infection, the RC-DNA CC migrates in the nucleus, and is converted into a plasmid-like CC covalently closed circular DNA (cccDNA). The activity of P protein does CC not seem to be necessary for cccDNA generation, and is presumably CC released from (+)DNA by host nuclear DNA repair machinery (By CC similarity). {ECO:0000250}. CC -!- CATALYTIC ACTIVITY: CC Reaction=DNA(n) + a 2'-deoxyribonucleoside 5'-triphosphate = DNA(n+1) + CC diphosphate; Xref=Rhea:RHEA:22508, Rhea:RHEA-COMP:17339, Rhea:RHEA- CC COMP:17340, ChEBI:CHEBI:33019, ChEBI:CHEBI:61560, ChEBI:CHEBI:173112; CC EC=2.7.7.7; Evidence={ECO:0000255|PROSITE-ProRule:PRU00405}; CC -!- CATALYTIC ACTIVITY: CC Reaction=DNA(n) + a 2'-deoxyribonucleoside 5'-triphosphate = DNA(n+1) + CC diphosphate; Xref=Rhea:RHEA:22508, Rhea:RHEA-COMP:17339, Rhea:RHEA- CC COMP:17340, ChEBI:CHEBI:33019, ChEBI:CHEBI:61560, ChEBI:CHEBI:173112; CC EC=2.7.7.49; Evidence={ECO:0000255|PROSITE-ProRule:PRU00405}; CC -!- CATALYTIC ACTIVITY: CC Reaction=Endonucleolytic cleavage to 5'-phosphomonoester.; EC=3.1.26.4; CC -!- ACTIVITY REGULATION: Activated by host HSP70 and HSP40 in vitro to be CC able to bind the epsilon loop of the pgRNA. Because deletion of the CC RNase H region renders the protein partly chaperone-independent, the CC chaperones may be needed indirectly to relieve occlusion of the RNA- CC binding site by this domain. CC -!- DOMAIN: Terminal protein domain (TP) is hepadnavirus-specific. Spacer CC domain is highly variable and separates the TP and RT domains. CC Polymerase/reverse-transcriptase domain (RT) and ribonuclease H domain CC (RH) are similar to retrovirus reverse transcriptase/RNase H (By CC similarity). {ECO:0000250}. CC -!- DOMAIN: The polymerase/reverse transcriptase (RT) and ribonuclease H CC (RH) domains are structured in five subdomains: finger, palm, thumb, CC connection and RNase H. Within the palm subdomain, the 'primer grip' CC region is thought to be involved in the positioning of the primer CC terminus for accommodating the incoming nucleotide. The RH domain CC stabilizes the association of RT with primer-template (By similarity). CC {ECO:0000250}. CC -!- SIMILARITY: Belongs to the hepadnaviridae P protein family. CC {ECO:0000305}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; K01834; AAA45742.1; -; Genomic_DNA. DR GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW. DR GO; GO:0003887; F:DNA-directed DNA polymerase activity; IEA:UniProtKB-KW. DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW. DR GO; GO:0003964; F:RNA-directed DNA polymerase activity; IDA:UniProtKB. DR GO; GO:0004523; F:RNA-DNA hybrid ribonuclease activity; IDA:UniProtKB. DR GO; GO:0006260; P:DNA replication; IEA:UniProtKB-KW. DR GO; GO:0001171; P:reverse transcription; IDA:GO_Central. DR FunFam; 3.30.70.270:FF:000058; Protein P; 1. DR Gene3D; 3.30.70.270; -; 1. DR Gene3D; 3.10.10.10; HIV Type 1 Reverse Transcriptase, subunit A, domain 1; 1. DR InterPro; IPR043502; DNA/RNA_pol_sf. DR InterPro; IPR001462; DNApol_viral_C. DR InterPro; IPR000201; DNApol_viral_N. DR InterPro; IPR052055; Hepadnavirus_pol/RT. DR InterPro; IPR043128; Rev_trsase/Diguanyl_cyclase. DR InterPro; IPR000477; RT_dom. DR PANTHER; PTHR33050; REVERSE TRANSCRIPTASE DOMAIN-CONTAINING PROTEIN; 1. DR PANTHER; PTHR33050:SF7; RIBONUCLEASE H; 1. DR Pfam; PF00336; DNA_pol_viral_C; 1. DR Pfam; PF00242; DNA_pol_viral_N; 1. DR Pfam; PF00078; RVT_1; 1. DR SUPFAM; SSF56672; DNA/RNA polymerases; 1. DR PROSITE; PS50878; RT_POL; 1. PE 3: Inferred from homology; KW DNA replication; DNA-binding; DNA-directed DNA polymerase; Endonuclease; KW Hydrolase; Magnesium; Metal-binding; Multifunctional enzyme; Nuclease; KW Nucleotidyltransferase; RNA-directed DNA polymerase; Transferase. FT CHAIN 1..836 FT /note="Protein P" FT /id="PRO_0000222327" FT DOMAIN 424..613 FT /note="Reverse transcriptase" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405" FT REGION 51..250 FT /note="Terminal protein domain (TP)" FT /evidence="ECO:0000250" FT REGION 251..414 FT /note="Spacer" FT /evidence="ECO:0000250" FT REGION 263..417 FT /note="Disordered" FT /evidence="ECO:0000256|SAM:MobiDB-lite" FT REGION 415..703 FT /note="Polymerase/reverse transcriptase domain (RT)" FT /evidence="ECO:0000250" FT REGION 704..836 FT /note="RnaseH domain (RH)" FT /evidence="ECO:0000250" FT COMPBIAS 285..296 FT /note="Basic and acidic residues" FT /evidence="ECO:0000256|SAM:MobiDB-lite" FT COMPBIAS 331..342 FT /note="Basic and acidic residues" FT /evidence="ECO:0000256|SAM:MobiDB-lite" FT COMPBIAS 364..375 FT /note="Basic residues" FT /evidence="ECO:0000256|SAM:MobiDB-lite" FT COMPBIAS 377..400 FT /note="Polar residues" FT /evidence="ECO:0000256|SAM:MobiDB-lite" FT BINDING 496 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="catalytic" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405" FT BINDING 563 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="catalytic" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405" FT BINDING 564 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="catalytic" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405" FT SITE 146 FT /note="Priming of reverse-transcription by covalently FT linking the first nucleotide of the (-)DNA" FT /evidence="ECO:0000250" SQ SEQUENCE 836 AA; 95276 MW; FFEB57CFF549A4F4 CRC64; MQKLTRNHWI GLGDCFGGIT TVYCGEKLKL LTIFLVCVLG CQLLRNIEVE MPRPLKQSLD QSRWLREAEK QLRVLENLVD SNLEEEKLKP QLSMGEDVQS PGKGEPLHPN VRAPLSHVVR AATIDLPRLG NKLPARHHLG KLSGLYQMKG CTFNPEWKVP DISDTHFNLD VVNECPSRNW KYLTPAKFWP KSISYFPVQV GVKPKYPDNV MQHESIVGKY LTRLYEAGIL YKRISKHLVT FKGQPYNWEQ QHLVNQHHIY DGATSSKING RQTDRRRRNT VKPTCRKDDP KRDFDMVRQV SNTRSRVRPC ANNGGDKHPP ESGSLACWGG KESRIIKSDS SRDSSAPVDS RGRPKSTRSF SPLSRRKTTG NHHHSSVFPS SVEATTRGRS TPGKSVSPRD SSAIPVRTSG ASDKNSPLEE ENVWYLRGNT SWPNRITGKL FLVDKNSRNT EEARLVVDFS QFSKGKNAMR FPRYWSPNLS TLRRILPVGM PRISLDLSQA FYHLPLNPAS SSRLAVSDGQ RVYYFRKAPM GVGLSPFLLH LFTTALGSEI SRRFNVWTFT YMDDFLLCHP NARHLNAISH AVCSFLQELG IRINFDKTTP SPVNEIRFLG YQIDENFMKI EESRWKELRT VIKKIKVGEW YDWKCIQRFV GHLNFVLPFT KGNIEMLKPM YAAITNQVNF SFSSSYRTLL YKLTMGVCKL RIKPKSSVPL PRVATDATPT HGAISHITGG SAVFAFSKVR DIHVQELLMS CLAKIMIKPR CLLSDSTFVC HKRYQTLPWH FAMLAKQLLK PIQLYFVPSK YNPADGPSRH KPPDWTAFPY TPLSKAIYIP HRLCGT //