4v08
From Proteopedia
Inhibited dimeric pseudorabies virus protease pUL26N at 2 A resolution
Structural highlights
FunctionSCAF_SUHVK Acts as a scaffold protein by binding major capsid protein in the cytoplasm, inducing the nuclear localization of both proteins. Multimerizes in the nucleus such as major capsid protein forms the icosahedral T=16 capsid. Autocatalytic cleavage releases the assembly protein, and subsequently abolishes interaction with major capsid protein. Cleavages products are evicted from the capsid before or during DNA packaging.[HAMAP-Rule:MF_04008] Protease that plays an essential role in virion assembly within the nucleus. Catalyzes the cleavage of the assembly protein after formation of the spherical procapsid. By that cleavage, the capsid matures and gains its icosahedral shape. The cleavage sites seem to include -Ala-Ser-, -Ala-Ala-, as well as Ala-Thr bonds. Assemblin and cleavages products are evicted from the capsid before or during DNA packaging.[HAMAP-Rule:MF_04008] Plays a major role in capsid assembly. Acts as a scaffold protein by binding major capsid protein. Multimerizes in the nucleus such as major capsid protein forms the icosahedral T=16 capsid. Cleaved by assemblin after capsid completion. The cleavages products are evicted from the capsid before or during DNA packaging.[HAMAP-Rule:MF_04008] Publication Abstract from PubMedHerpesviruses encode a characteristic serine protease with a unique fold and an active site that comprises the unusual triad Ser-His-His. The protease is essential for viral replication and as such constitutes a promising drug target. In solution, a dynamic equilibrium exists between an inactive monomeric and an active dimeric form of the enzyme, which is believed to play a key regulatory role in the orchestration of proteolysis and capsid assembly. Currently available crystal structures of herpesvirus proteases correspond either to the dimeric state or to complexes with peptide mimetics that alter the dimerization interface. In contrast, the structure of the native monomeric state has remained elusive. Here, we present the three-dimensional structures of native monomeric, active dimeric, and diisopropyl fluorophosphate-inhibited dimeric protease derived from pseudorabies virus, an alphaherpesvirus of swine. These structures, solved by X-ray crystallography to respective resolutions of 2.05, 2.10 and 2.03 A, allow a direct comparison of the main conformational states of the protease. In the dimeric form, a functional oxyanion hole is formed by a loop of 10 amino-acid residues encompassing two consecutive arginine residues (Arg136 and Arg137); both are strictly conserved throughout the herpesviruses. In the monomeric form, the top of the loop is shifted by approximately 11 A, resulting in a complete disruption of the oxyanion hole and loss of activity. The dimerization-induced allosteric changes described here form the physical basis for the concentration-dependent activation of the protease, which is essential for proper virus replication. Small-angle X-ray scattering experiments confirmed a concentration-dependent equilibrium of monomeric and dimeric protease in solution. Dimerization-Induced Allosteric Changes of the Oxyanion-Hole Loop Activate the Pseudorabies Virus Assemblin pUL26N, a Herpesvirus Serine Protease.,Zuhlsdorf M, Werten S, Klupp BG, Palm GJ, Mettenleiter TC, Hinrichs W PLoS Pathog. 2015 Jul 10;11(7):e1005045. doi: 10.1371/journal.ppat.1005045., eCollection 2015 Jul. PMID:26161660[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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