ID   R1AB_CVRSD              Reviewed;         307 AA.
AC   Q9WQ77;
DT   10-OCT-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1999, sequence version 1.
DT   29-SEP-2021, entry version 74.
DE   RecName: Full=Replicase polyprotein 1ab;
DE            Short=pp1ab;
DE   AltName: Full=ORF1ab polyprotein;
DE   Contains:
DE     RecName: Full=RNA-directed RNA polymerase;
DE              Short=Pol;
DE              Short=RdRp;
DE              EC=2.7.7.48;
DE     AltName: Full=nsp12;
DE   Flags: Fragment;
GN   Name=rep; ORFNames=1a-1b;
OS   Rat coronavirus (strain 681) (RCV-SDAV) (Sialodacryoadenitis virus
OS   SDAV-681).
OC   Viruses; Riboviria; Orthornavirae; Pisuviricota; Pisoniviricetes;
OC   Nidovirales; Cornidovirineae; Coronaviridae; Orthocoronavirinae;
OC   Betacoronavirus; Embecovirus.
OX   NCBI_TaxID=33740;
OH   NCBI_TaxID=10116; Rattus norvegicus (Rat).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=10392726; DOI=10.1016/s0168-1702(99)00017-9;
RA   Stephensen C.B., Casebolt D.B., Gangopadhyay N.N.;
RT   "Phylogenetic analysis of a highly conserved region of the polymerase gene
RT   from 11 coronaviruses and development of a consensus polymerase chain
RT   reaction assay.";
RL   Virus Res. 60:181-189(1999).
CC   -!- FUNCTION: The replicase polyprotein of coronaviruses is a
CC       multifunctional protein: it contains the activities necessary for the
CC       transcription of negative stranded RNA, leader RNA, subgenomic mRNAs
CC       and progeny virion RNA as well as proteinases responsible for the
CC       cleavage of the polyprotein into functional products.
CC   -!- FUNCTION: Non-structural protein 1: binds to the 40S ribosomal subunit
CC       and inhibits host translation. The nsp1-40S ribosome complex further
CC       induces an endonucleolytic cleavage near the 5'UTR of host mRNAs,
CC       targeting them for degradation. By suppressing host gene expression,
CC       nsp1 facilitates efficient viral gene expression in infected cells and
CC       evasion from host immune response (By similarity). {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate +
CC         RNA(n+1); Xref=Rhea:RHEA:21248, Rhea:RHEA-COMP:14527, Rhea:RHEA-
CC         COMP:17342, ChEBI:CHEBI:33019, ChEBI:CHEBI:61557, ChEBI:CHEBI:140395;
CC         EC=2.7.7.48; Evidence={ECO:0000255|PROSITE-ProRule:PRU00539};
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Ribosomal frameshifting; Named isoforms=2;
CC       Name=Replicase polyprotein 1ab; Synonyms=pp1ab;
CC         IsoId=Q9WQ77-1; Sequence=Displayed;
CC       Name=Replicase polyprotein 1a; Synonyms=pp1a, ORF1a polyprotein;
CC         IsoId=Q9WQ77-2; Sequence=Not described;
CC   -!- MISCELLANEOUS: [Isoform Replicase polyprotein 1ab]: Produced by -1
CC       ribosomal frameshifting at the 1a-1b genes boundary.
CC   -!- MISCELLANEOUS: [Isoform Replicase polyprotein 1a]: Produced by
CC       conventional translation. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the coronaviruses polyprotein 1ab family.
CC       {ECO:0000305}.
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DR   EMBL; AF124990; AAD32994.1; -; Genomic_RNA.
DR   SMR; Q9WQ77; -.
DR   GO; GO:0000166; F:nucleotide binding; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0003968; F:RNA-directed 5'-3' RNA polymerase activity; IEA:UniProtKB-KW.
DR   GO; GO:0039595; P:induction by virus of catabolism of host mRNA; IEA:UniProtKB-KW.
DR   GO; GO:0039657; P:suppression by virus of host gene expression; IEA:UniProtKB-KW.
DR   GO; GO:0006351; P:transcription, DNA-templated; IEA:InterPro.
DR   GO; GO:0039694; P:viral RNA genome replication; IEA:InterPro.
DR   InterPro; IPR043502; DNA/RNA_pol_sf.
DR   InterPro; IPR001205; RNA-dir_pol_C.
DR   InterPro; IPR007094; RNA-dir_pol_PSvirus.
DR   Pfam; PF00680; RdRP_1; 1.
DR   SUPFAM; SSF56672; SSF56672; 1.
DR   PROSITE; PS51948; COV_NSP12_RDRP; 1.
DR   PROSITE; PS50507; RDRP_SSRNA_POS; 1.
PE   3: Inferred from homology;
KW   Decay of host mRNAs by virus;
KW   Eukaryotic host gene expression shutoff by virus;
KW   Eukaryotic host translation shutoff by virus;
KW   Host gene expression shutoff by virus; Host mRNA suppression by virus;
KW   Host-virus interaction; Nucleotide-binding; Nucleotidyltransferase;
KW   Ribosomal frameshifting; RNA-binding; RNA-directed RNA polymerase;
KW   Transferase; Viral RNA replication.
FT   CHAIN           <1..>307
FT                   /note="RNA-directed RNA polymerase"
FT                   /id="PRO_0000037402"
FT   DOMAIN          <1..>307
FT                   /note="Nsp12 RNA-dependent RNA polymerase"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01293"
FT   DOMAIN          107..269
FT                   /note="RdRp catalytic"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00539"
FT   ACT_SITE        254
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01293"
FT   ACT_SITE        255
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01293"
FT   ACT_SITE        256
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01293"
FT   NON_TER         1
FT   NON_TER         307
SQ   SEQUENCE   307 AA;  34721 MW;  A1B2704FCCA38E3D CRC64;
     FNKFGKARLY YEALSFEEQD EIYAYTKRNV LPTLTQMNLK YAISAKNRAR TVAGVSILST
     MTGRMFHQKC LKSIAATRGV PVVIGTTKFY GGWDDMLRRL IKDVDSPVLM GWDYPKCDRA
     MPNILRIVSS LVLARKHDSC CSHTDRFYRL ANECAQVLSE IVMCGGCYYV KPGGTSSGDA
     TTAFANSVFN ICQAVSANVC SLMACNGHKI EDLSIRELQK RLYSNVYRAD HVDPAFVSEY
     YEFLNKHFSM MILSDDGVVC YNSEFASKGY IANISAFQQV LYYQNNVFMS EAKCWVETDI
     EKGPHEF