Asparagine proteases

Asparagine proteases in viruses plays a role in capsid maturation. They are a type of enzyme that catalyze the cleavage of peptide bonds without hydrolysis and use a asparagine residue in their active site.

(Wikipedia)

Enzymatic reaction: Enzymatic reaction:

Asn-endopeptidase

Mechanism
The active site consists of an asparagine and at least one acidic amino acid (Asp, Glu). The terminal asparagine azote acts as a nucleophile and attacks the carbonyl atom of the peptide bond, forming a succimide residue and cleaving the peptide bond; the acidic amino acid assists the process by stabilizing the reaction intermediates.

Genome	Order	Family	Function	Type	MEROPS family	Distribution (low incidence)	Clan (fold)	Interpro	UniProt exemplar
dsRNA	Nodamuvirales	Nodaviridae	Self-cleavage, Virion maturation	Asparagine (Asn/Ala)	Peptidase N1	Virus	NA	IPR000696	Capsid protein precursor
ssRNA+	Hepevirales	Alphatetraviridae	Self-cleavage, Virion maturation	Asparagine (Asn/?)	Peptidase N2	Virus	NA	IPR005313	Capsid protein precursor
ssRNA+	Durnavirales	Picobirnaviridae	Self-cleavage, Virion maturation	Asparagine	Peptidase N5	Virus	NE		Capsid protein precursor
dsRNA	Reovirales	Spinareoviridae, Orthoreovirus, Aquareovirus	Self-cleavage, Virion maturation	Asparagine	Peptidase N7	Virus	NC	IPR009113	Outer capsid protein mu-1
ssRNA+	Picornavirales	Picornaviridae, Enterovirus	Self-cleavage, Virion maturation	Asparagine	Peptidase N8	Virus	NA	IPR029053	Polyprotein
ssRNA+	Imitervirales	Mimiviridae	Self-cleavage, Intein	Asparagine	Peptidase N10	Animal, plant, protozoa, bacteria, archaea, virus	PD	IPR006141	DNA polymerase
ssRNA+	Algavirales	Phycodnaviridae	Self-cleavage, Intein	Asparagine	Peptidase N10	Animal, plant, protozoa, bacteria, archaea, virus	PD	IPR006141	DNA polymerase