Journal of General Virology 2006-05-01

Characterization of the murine leukemia virus protease and its comparison with the human immunodeficiency virus type 1 protease.

Anita Fehér, Péter Boross, Tamás Sperka, Gabriella Miklóssy, János Kádas, Péter Bagossi, Stephen Oroszlan, Irene T Weber, József Tözsér

Index: J. Gen. Virol. 87(Pt 5) , 1321-30, (2006)

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Abstract

The protease (PR) of Murine leukemia virus (MLV) was expressed in Escherichia coli, purified to homogeneity and characterized by using various assay methods, including HPLC-based, photometric and fluorometric activity measurements. The specificity of the bacterially expressed PR was similar to that of virion-extracted PR. Compared with human immunodeficiency virus type 1 (HIV-1) PR, the pH optimum of the MLV enzyme was higher. The specificity of the MLV PR was further compared with that of HIV-1 PR by using various oligopeptides representing naturally occurring cleavage sites in MLV and HIV-1, as well as by using bacterially expressed proteins having part of the MLV Gag. Inhibitors designed against HIV-1 PR were also active on MLV PR, although all of the tested ones were substantially less potent on this enzyme than on HIV-1 PR. Nevertheless, amprenavir, the most potent inhibitor against MLV PR, was also able to block Gag processing in MLV-infected cells. These results indicate that, in spite of the similar function in the life cycle of virus infection, the two PRs are only distantly related in their specificity.