In this study, a Monte Carlo simulation was designed to observe the self-assembly of the HIV-1 capsid protein. The simulation allowed a coarse grained model of the capsid protein with defined interaction sites to move freely in three dimensions using the Metropolis criterion. Observations were made as to which parameters affected the assembly the process. The ways in which the assembly were affected were also noted. It was found that proper dimerization of the capsid protein was necessary in order for the lattice to form properly. It was also found that a strong trimeric interface could be responsible for double-layered assemblies. Further studies may be conducted by further varying of parameters or reworking the dynamics of the simulation. The possible causes of curvature within the assembly still need to be researched further.

No description available.

The abundant cellular protein Cyclophilin A (CypA) was found to bind to HIV-1 capsid (CA) in 1993. Since that time, several complementary methods, including disruption of the binding interface by cyclosporine A, CA mutants, and CypA mutants, have been used to demonstrate that CypA acts within human target cells to promote HIV-1 infection. In contrast, in cells from non-human primates, CypA in target cells decreases HIV-1 infectivity, and it does so by promoting TRIM5α-mediated restriction. Using human cancer cell lines and the genetic methods available at the time, attempts to obtain evidence that CypA inhibits HIV-1 restriction by the human TRIM5α ortholog, let alone that human TRIM5α restricts HIV-1, were unsuccessful. Here we revisit the question of the mechanism by which CypA increases HIV-1 infectivity by exploiting lentiviral vectors optimized for primary human blood cells that serve as HIV-1 targets. Disruption of CA−CypA interaction is demonstrated to render HIV-1 vulnerable to endogenous human TRIM5α-mediated recognition and restriction, which occur prior to completion of reverse transcription. Identical findings were acquired with single-cycle vectors or with replication-competent viruses. Consistently, a previously identified, cyclosporine-resistant CA mutation A92E is also shown to confer resistance against restriction by human TRIM5α. Therefore, the results presented in this thesis reveal that HIV-1 exploits a host protein CypA bound to its CA to evade potent restriction by human TRIM5α. This finding not only answers a long-standing question regarding the role of CypA in HIV-1 infection, but also may reinvigorate the development of CypA inhibitors for treatment of HIV-1.