EC Number   |
Posttranslational Modification |
Reference |
|---|
   3.4.21.113 | proteolytic modification |
autocatalytic intramolecular cleavages of the enzyme, overview. One cleavable peptide bond occurs between Leu1781 and Met1782, giving rise to a helicase subunit of 55 kDa and, depending on the substrate, a NS2-3 fragment of 78 kDa, or a NS3 protease subunit of 26 kDa. A second intramolecular cleavage is mapped to the Leu1748/Lys1749 peptide bond that yields a proteolytically inactive NS3 fragment. Deletion of either of the cleavage site residues resultsin a loss ofRNAinfectivity, indicating the functional importance of amino acid identity at the respective positions |
732415 |
| 3.4.21.113 | proteolytic modification |
the viral RNA genome contains one large open reading frame (ORF) encoding a polyprotein of about 4,000 amino acids. The polyprotein is co- and posttranslationally processed into at least 12 mature proteins by viral and host proteases through cis (intramolecular) or trans (intermolecular) mechanisms. Core, Erns, E1, and E2 are the structural proteins that become part of the mature virion, and the eight nonstructural proteins Npro, p7, NS2, NS3, NS4A, NS4B, NS5A, and NS5B are involved in polyprotein processing, viral genome replication, and virus morphogenesis. cis-Cleavage events are essential to generate structurally independent proteases that may carry out trans-cleavages more efficiently than proteases in the form of polyprotein. Limitations are also applied to cis-cleavages, as the intramolecular recognition of the cleavage site requires the protease protein to adopt certain conformations that may not always achievable. Two minor autocleavage sites, Leu192/Met193 and Leu159/Lys160, are detected within the NS3 protease module |
754554 |
| 3.4.21.113 | proteolytic modification |
upon infection of the host cell, the viral RNA genome is translated into a polyprotein that is processed by cellular and viral proteases into the mature structural (SP) and nonstructural (NS) proteins. For members of the genus Pestivirus the array in the polyprotein is the following: NH2-Npro (N-terminal autoprotease), C (capsid protein, core), Erns (envelope protein RNase secreted), E1, E2, p7, NS2-3 (NS2 and NS3), NS4A, NS4B, NS5A, NS5B-COOH. The N-terminal autoprotease Npro generates its own C-terminus and thereby the N-terminus of the capsid protein core (C). Further cleavages releasing the structural proteins C, Erns, E1 and E2 as well as p7 are mediated by proteases residing in the endoplasmatic reticulum (ER). The cleavage between NS2 and NS3 is catalyzed by an autoprotease in NS2. The activity of the NS2 protease is temporally regulated by a cellular cofactor leading to significant amounts of uncleaved NS2-3 in pestivirus infected cells |
755207 |
