ABOUT THE MODEL: This model of HIV Protease shows the molecular surface for each chain of the protein and spheres for the inhibitor, indinavir. The probe radius of the molecular surface was 1.4 angstroms, about that of a water molecule. The scale is 10 million times actual size. This means that the molecule is 5.4 nanometers by 3.9 nanometers by 5.6 nanometers but the physical model swill be 5.4 centimeters by 3.9 centimeters by 5.6 centimeters.
ABOUT THE MOLECULE: HIV-1 protease (HIV PR) is an aspartic protease that is essential for the life-cycle of HIV, the retrovirus that causes AIDS. HIV PR cleaves newly synthesized polyproteins at the appropriate places to create the mature protein components of an infectious HIV virion. Without effective HIV PR, HIV virions remain uninfectious. Thus, mutation of HIV PR’s active site or inhibition of its activity disrupts HIV’s ability to replicate and infect additional cells, making HIV PR inhibition the subject of much pharmaceutical research.  (http://en.wikipedia.org/wiki/Hiv_protease)