HIV often changes its shape due to the presence of an enzyme called Reverse Transcriptase. This enzyme plays a crucial role in the replication process of the virus. It is responsible for converting the viral RNA into DNA, which can then be integrated into the host cell`s genetic material. This shape-changing ability of HIV is important for its survival and evasion from the host immune system. The constantly changing shape helps the virus to avoid detection by the immune system and develop resistance to antiviral drugs. Reverse Transcriptase is a key target for antiretroviral therapies, which work by inhibiting its activity and preventing viral replication. It is important to note that Enterokinase, Nucleotidase, and Nucleoditase are not enzymes directly involved in the replication or shape-changing ability of HIV.