Family N5

Family

Summary Holotypes Alignment Tree Genomes Structure Literature Architecture

Summary for family N5

Family type peptidase	N05.001 - picobirnavirus self-cleaving protein (Human picobirnavirus), MEROPS Accession MER0202949 (peptidase unit: 1-552)
Content of family	Family N5 includes self-cleaving endopeptidases
History	Identifier created: MEROPS 9.3 (7 September 2010) Picobirnaviruses are double-stranded RNA viruses. The virus particle is organized around a central icosahedral core capsid consisting of 120 identical subunits (Duquerroy et al., 2009). Each subunit undergoes an autoproteolytic cleavage, releasing a peptide that remains in the capsid associated with the RNA. Autoproteolytic cleavages of asparaginyl bonds are known also for capsid and coat proteins from nodaviruses (N1), tetraviruses (N2), reoviruses (N7) and picornaviruses (N8).
Catalytic type	Asparagine
Active site residues	N45
Active site	Cleavage occurs at Asn45, and this is assumed to be the nucleophile. In the nodavirus and tetravirus coat protein an active site dimer exists, in which the other component is an aspartate or glutamate. No equivalent residue in the picobirnavirus has been identified.
Activities and specificities	The only peptidase activity is release of an N-terminal 44-residue peptide from the N-terminus of the coat protein.
Molecular structure	The tertiary structure of the cleaved rabbit picobirnavirus coat protein (N05.001) has been solved, the structure is unrelated to that of any other peptidase and the rabbit picobirnavirus coat protein is the type structure for clan NE. The The mature N-terminus is a beta-hairpin more than 20 angstroms distant from the globular domain that comprises the rest of the molecule. In the crystal structure the N-terminal beta-hairpin of one monomer is embedded within the second monomer of the dimer. The released peptide is not visible in the solved tertiary structure but remains within the viral capsid associated with the RNA (Duquerroy et al., 2009).
Clan	NE

Distribution of family	Bacteria	-
	Archaea	-
	Protozoa	-
	Fungi	-
	Plants	-
	Animals	-
	Viruses	details

Biological functions	Picobirnavirus causes diarrhoea and gastroenteritis in human (Duquerroy et al., 2009).
Statistics for family N5	Sequences:	6
	Identifiers:	1
	Identifiers with PDB entries:	1
Downloadable files	Sequence library (FastA format)
	Sequence alignment (FastA format)
	Phylogenetic tree (Newick format)

Peptidases and Homologues	MEROPS ID	Structure
picobirnavirus self-cleaving protein	N05.001	-
Family N05 unassigned peptidases	unassigned	Yes