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United States Department of Agriculture

Agricultural Research Service

Title: Foot-and-Mouth Disease Virus L Peptidase

item Grubman, Marvin

Submitted to: Handbook of Proteolytic Enzymes
Publication Type: Other
Publication Acceptance Date: June 9, 2003
Publication Date: August 1, 2003

Technical Abstract: Foot-and-mouth disease virus (FMDV) and equine rhinitis A virus (ERAV) comprise the genus Aphthovirus within the family Picornaviridae. Three genera within this family, the aphthoviruses, the cardioviruses, and the newly designated erbovirus (ERBV) encode a leader (L) protein. The FMDV L-protein has been identified as a peptidase by sequence homology with papain and functional studies, and it has recently been demonstrated that ERAV and ERBV L-proteins also have peptidase activity, whereas the cardiovirus L protein is proteolytically inactive. The current nomenclature for picornavirus proteins was adopted at the third meeting of the European Study Group on the Molecular Biology of Picornaviruses and formalized by Rueckert & Wimmer (1984). A uniform nomenclature was devised at that time because of the complex cleavage pathways of these proteins and the additional variability of the numerous virus species within the family. The L-protein is defined as that region of the polyprotein preceding the capsid precursor protein, and the name was chosen because of its location in the polyprotein and to minimize possible confusion with other viral proteins. For FMDV there are two in-frame AUG codons at the beginning of the viral genome open reading frame, resulting in the synthesis of two L-proteins, Lab and Lb. Lb, the smaller of the two proteins, is the major species synthesized, and its sequence is highly conserved among the FMDV subtypes and serotypes that have been examined. The ERAV genome also possesses in-frame start sites in a similar position to the FMDV AUG codons, but these are present as two AUG pairs. In contrast to FMDV, in vitro results with ERAV bicistronic plasmids suggest that the second AUG of the first pair appears to be the dominant start site.

Last Modified: 4/17/2015