Protein: Protein P [Includes: DNA-directed DNA polymerase (EC 2.7.7.7); RNA-directed DNA polymerase (EC 2.7.7.49); Ribonuclease H (EC 3.1.26.4)] (Q69028)
Organism: Hepatitis B virus genotype C subtype ayr (isolate Human/Japan/Okamoto/-) (HBV-C)
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.
Sequence: MPLSYQHFRKLLLLDDEAGPLEEELPRLADEGLNRRVAEDLNLGNLNVSIPWTHKVGNFTGLYSSTVPVFNPDWKTPSFPHIHLQEDIINRCQQYVGPLTVNEKRRLKLIMPARFYPNLTKYLPLDKGIKPYYPEYAVNHYFKTRHYLHTLWKAGILYKRETTRSASFCGSPYSWEQELQHGRLVFQTSTRHGDESFCSQSSGILSRSPVGPCVRSQLKQSRLGLQPQQGSLARGKSGRSGSIWSRVHPTTRRPFGVEPSGSGHIDNTASSTSSCLHQSAVRKTAYSHLSTSKRQSSSGHAVELHNIPPSSARSQSEGPIFSCWWLQFRNSKPCSDYCLTHIVNLLEDWGPCTEHGEHNIRIPRTPARVTGGVFLVDKNPHNTTESRLVVDFSQFSRGSTHVSWPKFAVPNLQSLTNLLSSNLSWLSLDVSAAFYHIPLHPAAMPHLLVGSSGLPRYVARLSSTSRNINYQHGTMQNLHDSCSRNLYVSLLLLYKTFGRKLHLYSHPIILGFRKIPMGVGLSPFLLAQFTSAICSVVRRAFPHCLAFSYMDDVVLGAKSVQHLESLFTSITNFLLSLGIHLNPNKTKRWGYSLNFMGYVIGSWGTLPQEHIVQKLKQCFRKLPVNRPIDWKVCQRIVGLLGFAAPFTQCGYPALMPLYACIQSKQAFTFSPTYKAFLCKQYLNLYPVARQRSGLCQVFADATPTGWGLAIGHRRMRGTFVAPLPIHTAELLAACFARSRSGAKLIGTDNSVVLSRKYTSFPWLLGCAANWILRGTSFVYVPSALNPADDPSRGRLGLYRPLLHLPFRPTTGRTSLYAVSPSVPSHLPDRVHFASPLHVAWRPP
InterPro domains: - IPR043502: DNA/RNA polymerase superfamily (homologous_superfamily) [360-775]
- IPR000477: Reverse transcriptase domain (domain) [357-600]
- IPR043128: Reverse transcriptase/Diguanylate cyclase domain (homologous_superfamily) [515-598]
- IPR037531: Protein P (family) [1-843]
- IPR001462: Hepadnaviral P protein, C-terminal (domain) [601-833]
- IPR000201: Hepadnaviral P protein, N-terminal (domain) [4-352]
- IPR051320: Viral Replication and Maturation Polyprotein (family) [373-672]
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0005515 (protein binding)
Biological Process (BP): GO:0008150 (biological process), GO:0008152 (metabolic process), GO:0009987 (cellular process), GO:0044237 (cellular metabolic process), GO:0006807 (nitrogen compound metabolic process), GO:0071704 (organic substance metabolic process), GO:0009056 (catabolic process), GO:0044238 (primary metabolic process), GO:1901360 (organic cyclic compound metabolic process), GO:0006139 (nucleobase-containing compound metabolic process), GO:0046483 (heterocycle metabolic process), GO:0044248 (cellular catabolic process), GO:0006725 (cellular aromatic compound metabolic process), GO:0034641 (cellular nitrogen compound metabolic process), GO:1901575 (organic substance catabolic process), GO:0044260 (cellular macromolecule metabolic process), GO:0043170 (macromolecule metabolic process), GO:0034655 (nucleobase-containing compound catabolic process), GO:0009057 (macromolecule catabolic process), GO:0044270 (cellular nitrogen compound catabolic process), GO:0090304 (nucleic acid metabolic process), GO:0044265 (cellular macromolecule catabolic process), GO:0019439 (aromatic compound catabolic process), GO:1901361 (organic cyclic compound catabolic process), GO:0046700 (heterocycle catabolic process), GO:0006259 (DNA metabolic process), GO:0006308 (DNA catabolic process), GO:0090305 (nucleic acid phosphodiester bond hydrolysis), GO:0006401 (RNA catabolic process), GO:0090501 (RNA phosphodiester bond hydrolysis), GO:0090502 (RNA phosphodiester bond hydrolysis, endonucleolytic)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0018995 (host cellular component), GO:0033643 (host cell part), GO:0043657 (host cell), GO:0033646 (host intracellular part), GO:0043656 (host intracellular region), GO:0030430 (host cell cytoplasm)