ID   R1AB_IBVK               Reviewed;         521 AA.
AC   P12723;
DT   01-OCT-1989, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1989, sequence version 1.
DT   03-AUG-2022, entry version 78.
DE   RecName: Full=Replicase polyprotein 1ab;
DE            Short=pp1ab;
DE   AltName: Full=ORF1ab polyprotein;
DE   Contains:
DE     RecName: Full=Uridylate-specific endoribonuclease;
DE              EC=3.1.-.-;
DE     AltName: Full=NendoU;
DE     AltName: Full=nsp15;
DE     AltName: Full=p39;
DE   Contains:
DE     RecName: Full=Putative 2'-O-methyl transferase;
DE              EC=2.1.1.-;
DE     AltName: Full=nsp16;
DE     AltName: Full=p35;
DE   Flags: Fragment;
GN   Name=rep; ORFNames=1a-1b;
OS   Avian infectious bronchitis virus (strain KB8523) (IBV).
OC   Viruses; Riboviria; Orthornavirae; Pisuviricota; Pisoniviricetes;
OC   Nidovirales; Cornidovirineae; Coronaviridae; Orthocoronavirinae;
OC   Gammacoronavirus; Igacovirus.
OX   NCBI_TaxID=11126;
OH   NCBI_TaxID=9031; Gallus gallus (Chicken).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=2841803; DOI=10.1016/0042-6822(88)90603-4;
RA   Sutou S., Sato S., Okabe T., Nakai M., Sasaki N.;
RT   "Cloning and sequencing of genes encoding structural proteins of avian
RT   infectious bronchitis virus.";
RL   Virology 165:589-595(1988).
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: NendoU is a Mn(2+)-dependent, uridylate-specific enzyme,
CC       which leaves 2'-3'-cyclic phosphates 5' to the cleaved bond.
CC       {ECO:0000250}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Ribosomal frameshifting; Named isoforms=2;
CC       Name=Replicase polyprotein 1ab; Synonyms=pp1ab;
CC         IsoId=P12723-1; Sequence=Displayed;
CC       Name=Replicase polyprotein 1a; Synonyms=pp1a, ORF1a polyprotein;
CC         IsoId=P12723-2; 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}.
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DR   EMBL; M21515; AAA66577.1; -; Genomic_RNA.
DR   PIR; A29249; A29249.
DR   SMR; P12723; -.
DR   GO; GO:0004519; F:endonuclease activity; IEA:UniProtKB-KW.
DR   GO; GO:0008168; F:methyltransferase activity; IEA:UniProtKB-KW.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   CDD; cd20762; capping_2-OMTase_Nidovirales; 1.
DR   CDD; cd21161; NendoU_cv_Nsp15-like; 1.
DR   Gene3D; 3.40.50.11580; -; 1.
DR   Gene3D; 3.40.50.150; -; 1.
DR   InterPro; IPR037227; EndoU-like.
DR   InterPro; IPR043609; NendoU_nidovirus.
DR   InterPro; IPR043174; NSP15_middle_sf.
DR   InterPro; IPR044401; NSP15_NendoU_CoV.
DR   InterPro; IPR009461; NSP16_CoV-like.
DR   InterPro; IPR029063; SAM-dependent_MTases_sf.
DR   Pfam; PF06460; CoV_Methyltr_2; 1.
DR   Pfam; PF19215; CoV_NSP15_C; 1.
DR   SUPFAM; SSF142877; SSF142877; 1.
DR   SUPFAM; SSF53335; SSF53335; 1.
DR   PROSITE; PS51961; AV_NSP11N_COV_NSP15M; 1.
DR   PROSITE; PS51958; NENDOU; 1.
DR   PROSITE; PS51955; NIV_2_O_MTASE; 1.
PE   3: Inferred from homology;
KW   Endonuclease; Hydrolase; Methyltransferase; Nuclease;
KW   Ribosomal frameshifting; Transferase.
FT   CHAIN           <1..219
FT                   /note="Uridylate-specific endoribonuclease"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000037432"
FT   CHAIN           220..521
FT                   /note="Putative 2'-O-methyl transferase"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000037433"
FT   DOMAIN          <1..58
FT                   /note="AV-Nsp11N/CoV-Nsp15M"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01306"
FT   DOMAIN          75..216
FT                   /note="NendoU"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01303"
FT   DOMAIN          219..518
FT                   /note="Nidovirus-type SAM-dependent 2'-O-MTase"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01300"
FT   ACT_SITE        104
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01303"
FT   ACT_SITE        119
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01303"
FT   ACT_SITE        159
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01303"
FT   ACT_SITE        263
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01300"
FT   ACT_SITE        347
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01300"
FT   ACT_SITE        391
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01300"
FT   ACT_SITE        424
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01300"
FT   SITE            219..220
FT                   /note="Cleavage; by 3CL-PRO"
FT                   /evidence="ECO:0000250"
FT   NON_TER         1
SQ   SEQUENCE   521 AA;  58200 MW;  B979E3D32BCAFB74 CRC64;
     GGGGQSFLAA DNAVLVSTQC YKRHSYVEIP SNLLVQNGMS LKDGANLYVY KRVNGAFVTL
     PNTLNTQGRS YETFEPRSDV ERDFLDMSEE DFVEKYGKDL GLQHILYGEV DKPQLGGLHT
     VIGMYRLLRA NKLNAKSVTN SDSDVMQNYF VLADNGSYKQ VCTVVDLLLD DFLELLRNIL
     NEYGTNKSKV VTVSIDYHSI NFMTWFEDGS IKTCYPQLQS AWTCGYNMPE LYKVQNCVME
     PCNIPNYGVG ITLPSGIMMN VAKYTQLCQY LSKTTVCVPH NMRVMHFGAG SDKGVAPGST
     VLKQWLPEGT LLVDTDIVDY VSDAHVSVLS DCNKYKTEHK FDLVISDMYT DNDSKRKHGG
     VIANNGNDDV FIYLSSFLRN NLALGGSFAV KLTETSWHES LYDIAQDCAW WTMFCTAVNA
     SSSEAFLIGV NYLGASVKVK VSGKTLHANY IFWRNCNYLQ TSAYSIFDVA KFDLRLKATP
     VVNLKTEQKT DLVFNLIKCG KLLVRDVGNT SFTSDSFVCT M