P30028 (DPOL_HPBDC) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Protein P

Including the following 3 domains:

1. DNA-directed DNA polymerase
   EC=2.7.7.7
2. RNA-directed DNA polymerase
   EC=2.7.7.49
3. Ribonuclease H
   EC=3.1.26.4

Gene names

Name:

P

Organism

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

Taxonomic identifier

31510 [NCBI]

Taxonomic lineage

Viruses › Retro-transcribing viruses › Hepadnaviridae › Avihepadnavirus › Duck hepatitis B virus

Virus host

Anas (ducks) [TaxID: 8835]

Protein attributes

Sequence length	787 AA.
Sequence status	Complete.
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 relieve 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 nucleic acid phosphodiester bond hydrolysis Inferred from electronic annotation. Source: GOC
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 metal 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 – 787	787	Protein P		PRO_0000222328
Regions
	Domain	375 – 564	190	Reverse transcriptase
	Region	1 – 200	200	Terminal protein domain (TP) By similarity
	Region	201 – 365	165	Spacer By similarity
	Region	366 – 654	289	Polymerase/reverse transcriptase domain (RT) By similarity
	Region	655 – 787	133	RnaseH domain (RH) By similarity
Sites
	Metal binding	447	1	Magnesium; catalytic By similarity
	Metal binding	514	1	Magnesium; catalytic By similarity
	Metal binding	515	1	Magnesium; catalytic By similarity
	Site	96	1	Priming of reverse-transcription by covalently linking the first nucleotide of the (-)DNA By similarity

Sequences

	Sequence		Length	Mass (Da)
	P30028 [UniParc]. Last modified April 1, 1993. Version 1. Checksum: 1A99D7A656665180	FASTA	787	89,215
	10 20 30 40 50 60 MPQPLKQSLD QSKWLREAEK HLRELENLVD SNLEEEKLKP QLSMGEDVQS PGKGEPLHPN 70 80 90 100 110 120 VRAPLSHVVR AATIDLPRLG NKLPAKHHLG KLSGLYQMKG CTFNPEWKVP DISDTHFDLQ 130 140 150 160 170 180 VLNECPSRNW KYLTPAKFWP KSISYFPVQA GVKAKYPDNV MQHESIVGKY LTRLYEAGIL 190 200 210 220 230 240 YKRISKHLVT FKGQPYKWEH QYLVKQHQIP DGATTRKING RAENRRRGDP AKSISRPHDP 250 260 270 280 290 300 KRGCNMVRQI SNNRSSIRPC ANNGGDKHSP TTRRLACWGG KASRINQSYS SRDSSAPVDA 310 320 330 340 350 360 RGRSESAGSL SSLSGRKAAG NHHHSTLINP SVETTARGRS TPGEQISARD TSALPESRAS 370 380 390 400 410 420 RACNKDSSIK EENVWYLRGN TSWPNRITGK LFLVDKNSRN TTEARLVVDF SQFSKGKNAM 430 440 450 460 470 480 RFPRYWSPNL STLRRILPVG MPRISLDLSQ AFYHLPLNPA SSSRLAVSDG QRVYYFRKAP 490 500 510 520 530 540 MGVGLSPFLL HLFTTALGSE IARRFNVWTF TYMDDFLLCH PNARHLNSIS HAVCTFLQEL 550 560 570 580 590 600 GIRINFDKTT PSPVTEIRFL GYQIDQKFMK IEEDRWKELR TVIKKIKVGA WYDWKCIQRF 610 620 630 640 650 660 VGHLNFVLPF TKGNLEMLKP MYAAITNKVN FSFSSAYRTL LYKLTMGVCK LAIKPKSSVP 670 680 690 700 710 720 LPRVATDATP THGAISHITG GSAVFAFSKV RDIHIQELLM VCLAKLMIKP RCILTDSTFV 730 740 750 760 770 780 CHKRYQTLPW HFAMLAKQLL SPMQLYFVPS KYNPADGPSR HKPPDWTALT YTPLSKAIYI PHRLCGT

References

[1]	"Complete nucleotide sequence of a Chinese duck hepatitis B virus." Tong S., Mattes F., Teubner K., Blum H.E. Nucleic Acids Res. 18:6139-6139(1990) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Hepatitis B virus replication." Beck J., Nassal M. World J. Gastroenterol. 13:48-64(2007) [PubMed] [Europe PMC] [Abstract] Cited for: REVIEW.

Cross-references

Sequence databases
EMBL GenBank DDBJ	M21953 Genomic DNA. Translation: AAA45745.1.
PIR	JDVLW2. S12841.
3D structure databases
ProteinModelPortal	P30028.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
InterPro	IPR001462. DNApol_viral_C. IPR000201. DNApol_viral_N. IPR000477. RVT. [Graphical view]
Pfam	PF00336. DNA_pol_viral_C. 1 hit. PF00242. DNA_pol_viral_N. 1 hit. PF00078. RVT_1. 1 hit. [Graphical view]
PROSITE	PS50878. RT_POL. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

DPOL_HPBDC

Accession

Primary (citable) accession number: P30028

Entry history

Integrated into UniProtKB/Swiss-Prot:	April 1, 1993
Last sequence update:	April 1, 1993
Last modified:	April 3, 2013
This is version 51 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program