Protease cleavage

Crystallographic studies imply that although little sequence homology exists between the different protease cleavage sites, what is conserved is the shape that they adopt within the active site of the enzyme (Prabu-Jeyabalan et al. 2002). This shape has been termed the substrate envelope and represents the consensus volume overlapping the majority of the substrates. Most likely, HIV-1 protease recognizes a particular peptide sequence as being a substrate by a combination of accessibility and the shape the sequence can adopt. 

This signal peptide might have been eliminated by a trypsin-like protease cleavage (Benoist et al., 1987) since an Arg occurs in the CLPGl sequence, as in the case of PG of F. momUfonne and of PGII of A. niger (Bussink et al., 1991 Caprari et al., 1993). 

Yang, J. and Kramer, J.M. (1994) In vitro mutagenesis of Caenorhabditis elegans cuticle collagens identifies a potential subtilisin-like protease cleavage site and demonstrates that carboxyl domain disulfide bonding is required for normal function but not assembly. Molecular and Cellular Biology 14, 2722-2730. 

Berthelot, T, Talbot, J. C, Lain, G, Deleris, G. and Latxague, L. (2005). Synthesis of N epsilon-(7-diethylaminocoumarin-3-carboxyl)-and N epsilon-(7-methoxycoumarin-3-carboxyl)-L-Fmoc lysine as tools for protease cleavage detection by fluorescence. J. Pept. Sci. 11,153-160. 

Zucchini yellow mosaic virus Fusion with CP with protease cleavage anti-HIV proteins 37... 

Cowpea mosaic virus Fusion with CP, fusion to CP with protease cleavage site, complementation GFP, HIV, MEV, HRV, MV, CPV, S. aureus, Ps. aeruginosa 11, 12, 13, 31, 43, 58... 

Alexandrov, A., Dutta, K. and Pascal, S. M. (2001). MBP fusion protein with a viral protease cleavage site one-step cleavage/purification of insoluble proteins. Biotechniques 30, 1194—1198. 

Stols, L., Gu, M., Dieckman, L., Raffen, R., CoUart, F. R. and Donnelly, M. 1. (2002). Anew vector for high-throughput, ligation-independent cloning encoding a tobacco etch virus protease cleavage site. Protein Expr. Purif. 25, 8-15. 

Figure 4.7. a schematic presentation of the role of protease in processing of HIV gag (structural protein) and polymerase pol essential for producing infectious virus. With inactive HIV protease, the virus generated is immature and hence not infectious. The i indicates where HIV protease cleavage occurs in producing the pol gene product essential for viral replication. 

TEV) protease cleavage site is inserted between the binding/reactive group and the analytical handle. Labeling of proteomes with these probes followed by (strept) avidin resin incubation yields an enriched proteome. Trypsin digest followed by filtration yields a supernatant that can be analyzed by multidimensional LC-MS/MS analysis as in the MudPIT-ABPP experiment above. In the last step, the probe-labeled active site peptides are released from the resin by cleavage with TEV protease and subjected to MudPIT analysis (Lig. 5). 

CVB3 pathogenesis is complex and results in many changes to the host cell, known collectively as cytopathic effects (Carthy et al. 1998, 2003). Such changes include cell rounding, detachment from substrate, altered membrane permeability, and membrane fusion. Eventually these lead to lysis of host cells mainly through apoptosis or necrosis. Inhibition of host transcription and translation, and loss of cellular homeostasis due to direct viral protease cleavage of structural proteins such as dystrophin likely contribute to the cellular structure disruption and death of infected cells . 

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