Reviewed, UniProtKB/Swiss-Prot P03162 (DPOL_DHBV1)

Names and origin

Protein names

Recommended name:
    Protein P
Including the following 3 domains:
    1- Recommended name:
            DNA-directed DNA polymerase
              EC=2.7.7.7
    2- Recommended name:
            RNA-directed DNA polymerase
              EC=2.7.7.49
    3- Recommended name:
            Ribonuclease H
              EC=3.1.26.4

Gene names

Name:

P

Organism

Duck hepatitis B virus (strain DHBV-16) (DHBV) [Complete proteome]

Taxonomic identifier

489543 [NCBI]

Taxonomic lineage

Viruses › Retro-transcribing viruses › Hepadnaviridae › Orthohepadnavirus

Virus host

Anas (ducks) [TaxID: 8835]

Protein attributes

Sequence length	836 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Inferred from homology.

General annotation (Comments)

Function	Multifunctional enzyme that converts the viral RNA genome into dsDNA in viral cytoplasmic capsids. 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. Neo-synthesized pregenomic RNA (pgRNA) are encapsidated together with the P protein, and reverse-transcribed inside the nucleocapsid. Initiation of reverse-transcription occurs first by binding the epsilon loop on the pgRNA genome, and is initiated by protein priming, thereby the 5'-end of (-)DNA is covalently linked to P protein. Partial (+)DNA is synthesized from the (-)DNA template and generates the relaxed circular DNA (RC-DNA) genome. After budding and infection, the RC-DNA migrates in the nucleus, and is converted into a plasmid-like covalently closed circular DNA (cccDNA). The activity of P protein does not seem to be necessary for cccDNA generation, and is presumably released from (+)DNA by host nuclear DNA repair machinery By similarity.
Catalytic activity	Deoxynucleoside triphosphate + DNA(n) = diphosphate + DNA(n+1). Endonucleolytic cleavage to 5'-phosphomonoester.
Enzyme regulation	Activated by host HSP70 and HSP40 in vitro to be able to bind the epsilon loop of the pgRNA. Because deletion of the RNase H region renders the protein partly chaperone-independent, the chaperones may be needed indirectly to releive occlusion of the RNA-binding site by this domain.
Domain	Terminal protein domain (TP) is hepadnavirus-specific. Spacer domain is highly variable and separates the TP and RT domains. Polymerase/reverse-transcriptase domain (RT) and ribonuclease H domain (RH) are similar to retrovirus reverse transcriptase/RNase H By similarity. The polymerase/reverse transcriptase (RT) and ribonuclease H (RH) domains are 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 accommodating the incoming nucleotide. The RH domain stabilizes the association of RT with primer-template By similarity.
Sequence similarities	Belongs to the hepadnaviridae P protein family. Contains 1 reverse transcriptase domain.

Ontologies

Keywords
Biological process	DNA replication
Ligand	DNA-binding Magnesium Metal-binding
Molecular function	DNA-directed DNA polymerase Endonuclease Hydrolase Nuclease Nucleotidyltransferase RNA-directed DNA polymerase Transferase
Technical term	Complete proteome Multifunctional enzyme
Gene Ontology (GO)
Biological process	RNA-dependent DNA replication Inferred from electronic annotation. Source: InterPro
Molecular function	DNA binding Inferred from electronic annotation. Source: UniProtKB-KW DNA-directed DNA polymerase activity Inferred from electronic annotation. Source: UniProtKB-KW RNA binding Inferred from electronic annotation. Source: InterPro RNA-directed DNA polymerase activity Inferred from electronic annotation. Source: UniProtKB-KW magnesium ion binding Inferred from electronic annotation. Source: UniProtKB-KW ribonuclease H activity Inferred from electronic annotation. Source: EC
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 836	836	Protein P		PRO_0000222327
Regions
	Domain	424 – 613	190	Reverse transcriptase
	Region	51 – 250	200	Terminal protein domain (TP) By similarity
	Region	251 – 414	164	Spacer By similarity
	Region	415 – 703	289	Polymerase/reverse transcriptase domain (RT) By similarity
	Region	704 – 836	133	RnaseH domain (RH) By similarity
Sites
	Metal binding	496	1	Magnesium; catalytic By similarity
	Metal binding	563	1	Magnesium; catalytic By similarity
	Metal binding	564	1	Magnesium; catalytic By similarity
	Site	146	1	Priming of reverse-transcription by covalently linking the first nucleotide of the (-)DNA By similarity

Sequences

	Sequence		Length	Mass (Da)
	P03162-1 [UniParc]. Last modified October 1, 1996. Version 2. Checksum: FFEB57CFF549A4F4	FASTA	836	95,276
	10 20 30 40 50 60 MQKLTRNHWI GLGDCFGGIT TVYCGEKLKL LTIFLVCVLG CQLLRNIEVE MPRPLKQSLD 70 80 90 100 110 120 QSRWLREAEK QLRVLENLVD SNLEEEKLKP QLSMGEDVQS PGKGEPLHPN VRAPLSHVVR 130 140 150 160 170 180 AATIDLPRLG NKLPARHHLG KLSGLYQMKG CTFNPEWKVP DISDTHFNLD VVNECPSRNW 190 200 210 220 230 240 KYLTPAKFWP KSISYFPVQV GVKPKYPDNV MQHESIVGKY LTRLYEAGIL YKRISKHLVT 250 260 270 280 290 300 FKGQPYNWEQ QHLVNQHHIY DGATSSKING RQTDRRRRNT VKPTCRKDDP KRDFDMVRQV 310 320 330 340 350 360 SNTRSRVRPC ANNGGDKHPP ESGSLACWGG KESRIIKSDS SRDSSAPVDS RGRPKSTRSF 370 380 390 400 410 420 SPLSRRKTTG NHHHSSVFPS SVEATTRGRS TPGKSVSPRD SSAIPVRTSG ASDKNSPLEE 430 440 450 460 470 480 ENVWYLRGNT SWPNRITGKL FLVDKNSRNT EEARLVVDFS QFSKGKNAMR FPRYWSPNLS 490 500 510 520 530 540 TLRRILPVGM PRISLDLSQA FYHLPLNPAS SSRLAVSDGQ RVYYFRKAPM GVGLSPFLLH 550 560 570 580 590 600 LFTTALGSEI SRRFNVWTFT YMDDFLLCHP NARHLNAISH AVCSFLQELG IRINFDKTTP 610 620 630 640 650 660 SPVNEIRFLG YQIDENFMKI EESRWKELRT VIKKIKVGEW YDWKCIQRFV GHLNFVLPFT 670 680 690 700 710 720 KGNIEMLKPM YAAITNQVNF SFSSSYRTLL YKLTMGVCKL RIKPKSSVPL PRVATDATPT 730 740 750 760 770 780 HGAISHITGG SAVFAFSKVR DIHVQELLMS CLAKIMIKPR CLLSDSTFVC HKRYQTLPWH 790 800 810 820 830 FAMLAKQLLK PIQLYFVPSK YNPADGPSRH KPPDWTAFPY TPLSKAIYIP HRLCGT

References

[1]	"Nucleotide sequence of a cloned duck hepatitis B virus genome: comparison with woodchuck and human hepatitis B virus sequences." Mandart E., Kay A., Galibert F. J. Virol. 49:782-792(1984) [PubMed: 6699938] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Mapping of the cohesive overlap of duck hepatitis B virus DNA and of the site of initiation of reverse transcription." Molnar-Kimber K.L., Summers J.W., Mason W.S. J. Virol. 51:181-191(1984) [PubMed: 6328037] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 794-836.
[3]	"Efficient Hsp90-independent in vitro activation by Hsc70 and Hsp40 of duck hepatitis B virus reverse transcriptase, an assumed Hsp90 client protein." Beck J., Nassal M. J. Biol. Chem. 278:36128-36138(2003) [PubMed: 12851401] [Abstract] Cited for: ACTIVATION BY HOST HSC70 AND HSP40.
[4]	"Chaperones activate hepadnavirus reverse transcriptase by transiently exposing a C-proximal region in the terminal protein domain that contributes to epsilon RNA binding." Stahl M., Beck J., Nassal M. J. Virol. 81:13354-13364(2007) [PubMed: 17913810] [Abstract] Cited for: ACTIVATION BY HOST CHAPERONES.
[5]	"Hepatitis B virus replication." Beck J., Nassal M. World J. Gastroenterol. 13:48-64(2007) [PubMed: 17206754] [Abstract] Cited for: REVIEW.

Cross-references

Sequence databases
EMBLGenBankDDBJ	K01834 Genomic DNA. Translation: AAA45742.1.
3D structure databases
ModBase	Search...
Family and domain databases
InterPro	IPR000477. DNA_pol_RVTase. IPR001462. DNApol_viral_C. IPR000201. DNApol_viral_N. [Graphical view]
Pfam	PF00336. DNA_pol_viral_C. 1 hit. PF00242. DNA_pol_viral_N. 1 hit. PF00078. RVT_1. 1 hit. [Graphical view]
ProDom	PD000814. DNApol_viral_C. 1 hit. [Graphical view] [Entries sharing at least one domain]
PROSITE	PS50878. RT_POL. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

DPOL_DHBV1

Accession

Primary (citable) accession number: P03162

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	October 1, 1996
Last modified:	June 16, 2009
This is version 54 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Virus (Virus annotation project)