ANALYSIS OF INTERACTIONS IN COMPLEXES OF
HIV-1 PROTEASE AND ITS PEPTIDOMIMETIC INHIBITOR
T. Skálová, H. Petroková, J. Hašek, J. Dohnálek, E. Buchtelová, J. Dušková
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovského nám. 2, 162 06 Praha 6, Czech Republic
HIV-1 protease is a 22 kDa protein of the human immunodeficiency virus. The function of this protein is to cleave polyprotein of immature virus and thus to contribute to formation of active matured virus. Inhibition of the protease is therefore one of possible ways of fighting with disease AIDS, caused by the human immunodeficiency virus.
Our research was focused on interaction analysis of HIV-1 protease and its peptidomimetic inhibitor Boc-Phe-Ψ[CH2CH2NH]-Phe-Glu-Phe-NH2, denoted as OE. The inhibitor was developed in the laboratory of J. Konvalinka (Institute of Organic Chemistry and Biochemistry, Academy of Sciences CR). Native and mutant (A71V, V82T, I84V) HIV-1 protease were expressed and purified in the laboratories of J. Sedláček (Institute of Molecular Genetics, Academy of Sciences CR) and J. Konvalinka. In our research group, crystallization of complexes of OE with native and mutant protease was performed, X-ray diffraction of crystals on the synchrotron source of radiation was measured and structures of both complexes were determined (, ).
As a result, we have two structures with R-factors 18 % (native protease complex, diffraction limit 2.45 Å) and 20.3 % (mutant protease complex, diffraction limit 2.2 Å). Both complexes crystallized in space group P61 and inhibitor OE was found in the active site in two approximately C2 symmetrical positions, following thus pseudo-symmetry of the protease. This fact makes interpretation of interactions between the protease and inhibitor more difficult. Therefore, standard structural analysis of contacts between the protease and inhibitor was completed by two energy analyses of interactions in the active site. The inhibitor binding modes to both proteases are similar from the structural point of view and interpretation of small details could be ambiguous. However, energy analysis of both complexes confirms the interpretation of changes caused by mutation of the protease. Mutated residue Thr 182 forms an aromatic hydrogen bond to the inhibitor phenyl group in P1 position. Mutation I84V causes a decrease in van der Waals interaction between residue 84 and the OE inhibitor.
Acknowledgment. The research was supported by the Grant Agency of the Academy of Sciences of the Czech Republic (projects A4050811/1998 and B4050312/2003) and by the Academy of Sciences of the Czech Republic (project AVOZ4050913).
 T. Skálová, J. Hašek, J. Dohnálek, H. Petroková, E. Buchtelová, Mutant HIV-1 protease complexed with tetrapeptide inhibitor. Preliminary report, Acta Phys. Pol. A, 101 (2002), 659-663.
 H. Petroková, unpublished results.