AC   PRU01452;
DC   Domain;
TR   PROSITE; PS52108; MNV_L_PRNTASE; 1; level=0
XX
Names: Mononegavirales order large (L) protein polyribonucleotidyl transferase (PRNTase or capping) domain
Function: The L PRNTase domain is responsible for the addition of a 5' cap to
 nascent viral mRNAs. The L PRNTase (EC 2.7.7.88) domain transfers 5'-
 monophospho-RNA (pRNA) from 5'-triphospho-RNA (pppRNA) to GDP via a covalent
 enzyme (L)-pRNA intermediate to yield the cap on RNA. In addition, the
 PRNTase domain contains a priming loop, which is thought to facilitate de
 novo initiation. The PRNTase priming loop undergoes temporal conformational
 changes that regulate initiation, elongation, and mRNA capping during RNA
 synthesis.
XX
DE   + AltName: Short=Protein L;
DE   + AltName: EC=2.7.7.88;
XX
CC   -!- FUNCTION: RNA-directed RNA polymerase that catalyzes the
CC       transcription of viral mRNAs, their capping and polyadenylation.
CC       The template is composed of the viral RNA tightly encapsidated by
CC       the nucleoprotein (N). The viral polymerase binds to the genomic
CC       RNA at the 3' leader promoter, and transcribes subsequently all
CC       viral mRNAs with a decreasing efficiency. The first gene is the
CC       most transcribed, and the last the least transcribed. The viral
CC       phosphoprotein acts as a processivity factor. Capping is
CC       concomitant with initiation of mRNA transcription. Indeed, a GDP
CC       polyribonucleotidyl transferase (PRNTase) adds the cap structure
CC       when the nascent RNA chain length has reached few nucleotides.
CC       Ribose 2'-O methylation of viral mRNA cap precedes and facilitates
CC       subsequent guanine-N-7 methylation, both activities being carried
CC       by the viral polymerase. Polyadenylation of mRNAs occur by a
CC       stuttering mechanism at a slipery stop site present at the end
CC       viral genes. After finishing transcription of a mRNA, the
CC       polymerase can resume transcription of the downstream gene.
CC   -!- CATALYTIC ACTIVITY: Reaction=GTP + H2O = GDP + phosphate + H(+);
CC       Xref=Rhea:RHEA:19669, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC       ChEBI:CHEBI:37565, ChEBI:CHEBI:43474, ChEBI:CHEBI:58189;
CC   -!- CATALYTIC ACTIVITY: Reaction=a 5'-end triphospho-adenylyl-
CC       adenylyl-cytidylyl-adenosine in mRNA + GDP + H(+) = a 5'-end (5'-
CC       triphosphoguanosine)-adenylyl-adenylyl-cytidylyl-adenosine in mRNA
CC       + diphosphate; Xref=Rhea:RHEA:65436, Rhea:RHEA-COMP:16797,
CC       Rhea:RHEA-COMP:16799, ChEBI:CHEBI:15378, ChEBI:CHEBI:33019,
CC       ChEBI:CHEBI:58189, ChEBI:CHEBI:156484, ChEBI:CHEBI:156503;
CC       EC=2.7.7.88;
XX
GO   GO:0005524; F:ATP binding
GO   GO:0003924; F:GTPase activity
GO   GO:0030430; C:host cell cytoplasm
case <FTGroup:1> or <FTGroup:2> or <FTGroup:3> or <FTGroup:4> or <FTGroup:5>
GO   GO:0008270; F:zinc ion binding
GO   GO:0046872; F:metal ion binding
XX
KW   Metal-binding
KW   Zinc
end case
XX
KW   Nucleotide-binding
KW   Nucleotidyltransferase
KW   Transferase
KW   Viral RNA replication
KW   mRNA capping
KW   mRNA processing
KW   Hydrolase
KW   Host cytoplasm
XX
FT   From: PS52108
FT   DOMAIN          from..to
FT                   /note="PRNTase (capping) #"
FT   REGION          293..309
FT                   /note="priming-capping loop #"
FT   MOTIF           225..240
FT                   /note="PRNTase motif A #"
FT   Condition: R-x(3)-W-x*-G-x(3)-[PA]
FT   MOTIF           288..293
FT                   /note="PRNTase motif B #"
FT   Condition: [YW]-x-G-[ST]-x-T
FT   MOTIF           323
FT                   /note="PRNTase motif C #"
FT   Condition: W
FT   MOTIF           364..365
FT                   /note="PRNTase motif D #"
FT   Condition: H-[RK]
FT   MOTIF           404..413
FT                   /note="PRNTase motif E #"
FT   Condition: x(5)-[FY]-Q-x(3)
FT   ACT_SITE        364
FT                   /note="Nucleophile; for GDP polyribonucleotidyltransferase #"
FT   Condition: H
case <AnyFeature:PS52108:216-446=C-x*-E-x*-C-x(2)-C>
FT   BINDING         216
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 1; Condition: C
FT   BINDING         244
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 1; Condition: E
FT   BINDING         443
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 1; Condition: C
FT   BINDING         446
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 1; Condition: C
else case <AnyFeature:PS52108:216-446=C-x*-E-x*-C-C>
FT   BINDING         216
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: C
FT   BINDING         244
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: E
FT   BINDING         445
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: C
FT   BINDING         446
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: C
else case <AnyFeature:PS52108:216-443=C-x*-E-x*-C-C>
FT   BINDING         216
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: C
FT   BINDING         244
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: E
FT   BINDING         442
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: C
FT   BINDING         443
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#1"
FT                   /ligand_note="structural"
FT   Group: 2; Condition: C
end case
case <AnyFeature:PS52108:257-440=C-x(2)-C-x*-H-x-H>
FT   BINDING         257
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 3; Condition: C
FT   BINDING         260
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 3; Condition: C
FT   BINDING         438
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 3; Condition: H
FT   BINDING         440
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 3; Condition: H
else case <AnyFeature:PS52108:257-440=C-C-x*-H-x-H>
FT   BINDING         257
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 4; Condition: C
FT   BINDING         258
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 4; Condition: C
FT   BINDING         438
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 4; Condition: H
FT   BINDING         440
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 4; Condition: H
else case <AnyFeature:PS52108:257-440=C-x-C-x*-H-x-H>
FT   BINDING         257
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 5; Condition: C
FT   BINDING         259
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 5; Condition: C
FT   BINDING         438
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 5; Condition: H
FT   BINDING         440
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="#2"
FT                   /ligand_note="structural"
FT   Group: 5; Condition: H
end case
XX
Chop: Nter=0; Cter=0;
Size: 443-505;
Related: None;
Repeats: 1;
Topology: Undefined;
Example: P03523;
Scope:
 Viruses; Mononegavirales
Comments: None;
XX
# Version: 1
# Last updated date: 2026-06-10
# Created date: 2026-06-10
//