C-terminal residues of mature human T-lymphotropic virus type 1 protease are critical for dimerization and catalytic activity

János Kádas , Péter Boross , Irene T Weber , Péter Bagossi , Krisztina Matúz , József Tözsér (1)

1 Biochemistry and Molecular Biology

Human T-lymphotropic virus type 1 (HTLV-1) is associated with a number of human diseases. Its protease is essential for the virus replication, and similar to the human immunodeficiency virus type 1 (HIV-1) protease, it is a potential target for chemotherapy. The primary sequence of HTLV-1 protease is substantially longer compared to that of HIV-1 protease, and the role of the ten C-terminal residues is controversial. We have expressed C-terminally truncated forms of the HTLV-1 protease with and without N-terminal histidine tags. Removal of five C-terminal residues caused four- to fourtyfold decrease of the specificity constants, while the removal of an additional five C-terminal residues rendered the protease completely inactive. The addition of the N-terminal histidine tag dramatically decreased the activity of the HTLV-1 protease forms. Pull-down experiments carried out with histidine-tagged forms, gelfiltration experiments and dimerization assays provided the first unequivocal experimental data for the role of the C-terminal residues in dimerization of the enzyme. There is a hydrophobic tunnel on the surface of HTLV-1 protease close to the terminal ends that is absent in HIV-1 protease. This hydrophobic tunnel can accommodate the C-terminal extra residues of HTLV-1 protease, which was predicted to stabilize the dimer of the full-length enzyme and provides an alternative target site for protease inhibition.

Mots clés: Life Sciences

János Kádas, Péter Boross, Irene T Weber, Péter Bagossi, Krisztina Matúz, et al.. C-terminal residues of mature human T-lymphotropic virus type 1 protease are critical for dimerization and catalytic activity. Biochemical Journal, 2008, 416 (3), pp.357-364. ⟨10.1042/BJ20071132⟩. ⟨hal-00478876⟩