ProRule PRU01452

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PURL: https://purl.expasy.org/prosite/rule/PRU01452

General rule information [?]

Accession	PRU01452
Dates	10-JUN-2026 (Created) 10-JUN-2026 (Last updated, Version )
Data class	Domain;
Predictors	PROSITE; PS52108; MNV_L_PRNTASE
Name	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.
Scope(s)	Viruses Mononegavirales
Example(s)	P03523 (L_VSIVA);

Propagated annotation [?]

Identifier, protein and gene names [?]

Protein name

+ AltName: Short=Protein L;
+ AltName: EC=2.7.7.88;

Comments [?]

FUNCTION	RNA-directed RNA polymerase that catalyzes the transcription of viral mRNAs, their capping and polyadenylation. The template is composed of the viral RNA tightly encapsidated by the nucleoprotein (N). The viral polymerase binds to the genomic RNA at the 3' leader promoter, and transcribes subsequently all viral mRNAs with a decreasing efficiency. The first gene is the most transcribed, and the last the least transcribed. The viral phosphoprotein acts as a processivity factor. Capping is concomitant with initiation of mRNA transcription. Indeed, a GDP polyribonucleotidyl transferase (PRNTase) adds the cap structure when the nascent RNA chain length has reached few nucleotides. Ribose 2'-O methylation of viral mRNA cap precedes and facilitates subsequent guanine-N-7 methylation, both activities being carried by the viral polymerase. Polyadenylation of mRNAs occur by a stuttering mechanism at a slipery stop site present at the end viral genes. After finishing transcription of a mRNA, the polymerase can resume transcription of the downstream gene.
CATALYTIC ACTIVITY	Reaction=GTP + H2O = GDP + phosphate + H(+); Xref=Rhea:RHEA:19669, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:37565, ChEBI:CHEBI:43474, ChEBI:CHEBI:58189;
CATALYTIC ACTIVITY	Reaction=a 5'-end triphospho-adenylyl- adenylyl-cytidylyl-adenosine in mRNA + GDP + H(+) = a 5'-end (5'- triphosphoguanosine)-adenylyl-adenylyl-cytidylyl-adenosine in mRNA + diphosphate; Xref=Rhea:RHEA:65436, Rhea:RHEA-COMP:16797, Rhea:RHEA-COMP:16799, ChEBI:CHEBI:15378, ChEBI:CHEBI:33019, ChEBI:CHEBI:58189, ChEBI:CHEBI:156484, ChEBI:CHEBI:156503; EC=2.7.7.88;

Keywords [?]

Metal-binding
Zinc
end case

Gene Ontology [?]

GO:0005524; Molecular function:ATP binding
GO:0003924; Molecular function:GTPase activity
GO:0030430; Cellular component:host cell cytoplasm
case <FTGroup:1> or <FTGroup:2> or <FTGroup:3> or <FTGroup:4> or <FTGroup:5>
GO:0008270; Molecular function:zinc ion binding
GO:0046872; Molecular function:metal ion binding

Features [?]

From: PS52108
Key	From	To	Description	Tag	Condition	FTGroup
DOMAIN	from	to	/note="PRNTase (capping) #"
REGION	293	309	/note="priming-capping loop #"
MOTIF	225	240	/note="PRNTase motif A #"		R-x(3)-W-x*-G-x(3)-[PA]
MOTIF	288	293	/note="PRNTase motif B #"		[YW]-x-G-[ST]-x-T
MOTIF	323	323	/note="PRNTase motif C #"		W
MOTIF	364	365	/note="PRNTase motif D #"		H-[RK]
MOTIF	404	413	/note="PRNTase motif E #"		x(5)-[FY]-Q-x(3)
ACT_SITE	364	364	/note="Nucleophile; for GDP polyribonucleotidyltransferase #"		H
case <AnyFeature:PS52108:216-446=C-x-E-x-C-x(2)-C>
BINDING	216	216	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	1
BINDING	244	244	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		E	1
BINDING	443	443	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	1
BINDING	446	446	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	1
else case <AnyFeature:PS52108:216-446=C-x-E-x-C-C>
BINDING	216	216	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	2
BINDING	244	244	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		E	2
BINDING	445	445	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	2
BINDING	446	446	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	2
else case <AnyFeature:PS52108:216-443=C-x-E-x-C-C>
BINDING	216	216	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	2
BINDING	244	244	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		E	2
BINDING	442	442	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	2
BINDING	443	443	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#1" /ligand_note="structural"		C	2
end case
case <AnyFeature:PS52108:257-440=C-x(2)-C-x*-H-x-H>
BINDING	257	257	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		C	3
BINDING	260	260	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		C	3
BINDING	438	438	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		H	3
BINDING	440	440	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		H	3
else case <AnyFeature:PS52108:257-440=C-C-x*-H-x-H>
BINDING	257	257	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		C	4
BINDING	258	258	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		C	4
BINDING	438	438	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		H	4
BINDING	440	440	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		H	4
else case <AnyFeature:PS52108:257-440=C-x-C-x*-H-x-H>
BINDING	257	257	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		C	5
BINDING	259	259	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		C	5
BINDING	438	438	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		H	5
BINDING	440	440	/ligand="Zn(2+)" /ligand_id="ChEBI:CHEBI:29105" /ligand_label="#2" /ligand_note="structural"		H	5
end case

Additional information [?]

Size range	443-505 amino acids
Related rules	None
Fusion	None
Repeats	1
Topology	Undefined

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