|Family type peptidase||N07.001 - reovirus type 1 coat protein (Mammalian orthoreovirus 1), MEROPS Accession MER0191303 (peptidase unit: 2-708)|
|Content of family||Family N7 includes self-cleaving endopeptidases|
Identifier created: MEROPS 9.3 (7 September 2010)|
Reoviruses are double-stranded DNA viruses. The virus particle consists of two concentric, icosahedral protein capsids surrounding a ten segment, double-stranded RNA genome (Zhang etal, 2005). One of the capsid proteins, known as mu-1, undergoes an autoproteolytic cleavage, releasing a peptide that remains in the capsid associated with the RNA. Similar autoproteolytic cleavages are known for coat proteins from nodaviruses (family N1), tetraviruses (N2), picobirnaviruses (N5) and picornaviruses (N8).
|Active site residues||N42 |
|Active site||Cleavage occurs at Asn42, and this is assumed to be the nucleophile. Substitution of Asn42 prevents cleavage (Odegard et al., 2004). Presumably, by analogy to other coat proteins a second residue is required to form a catalytic dyad, which is Asp in the nodavirus coat protein (N01.001) or Glu in the tetravirus coat protein (N02.001).|
|Activities and specificities||The only peptidase activity is release an N-terminal 42-residue peptide from the N-terminus of the coat protein.|
|Molecular structure||The mu-1 protein is myristoylated at its N-terminus. The tertiary structure of the cleaved mu-1 protein has been solved and shows a fold unrelated to that of any other peptidase (Zhang et al., 2005). The structure of the mu-1 protein is therefore the type structure for clan NC.|