Date of Award
Doctor of Philosophy
Ricardo A. Bernal
Structural studies on proteins provide valuable knowledge, from information about their fundamental nature, to laying a foundation for rational drug design. Here, we study two proteins, a human mitochondrial chaperonin heat shock protein 60 (Hsp60) and the main structural HIV-1 protein capsid (CA). We focus on the structural nature of both proteins to try to understand their role in disease and elucidate the mechanism of potential drug treatments. Hsp60 is a chaperonin found in human mitochondria that is responsible for assisting client proteins reach their native, functional, state. The mechanism by which it catalyzes protein folding, however, has not been fully elucidated. Much of what is known about Hsp60 is borrowed from its bacterial homolog GroEL, but recently, data has shown that they may employ significantly different mechanisms. We investigate the mechanism by attempting to solve the structure of the chaperonin in its different conformational states using cryo-electron microscopy. Our results indicate that Hsp60 functions via a highly dynamic mechanism involving significant conformational changes. We obtained cryo-EM structures that show Hsp60 in its apo conformation forming a double ring complex, followed by an ATP bound double ring structure in complex with its co-chaperonin Hsp10, and a novel single ring ADP bound intermediate. Our data suggests that Hsp60 incorporates conformations that have not been observed in GroEL, indicating a unique and novel mechanism of action. We also use EM to study the interaction between HIV capsid protein and functionalized fullerenes, some of which have been recently shown to be potent HIV maturation inhibitors. Our studies consist of creating in-vitro assembly models to evaluate the effect of fullerenes on capsid assembly inhibition. Currently, there are no HIV treatments that target HIV capsid assembly. New targets for drug design are crucial due to the rapid emergence of drug-resistant HIV strains, resulting from a very high mutation rate in HIV.
Received from ProQuest
Rodriguez, Alejandro, "Structural and Biochemical Studies on Disease Associated Proteins: Heat Shock Protein 60 and HIV Capsid" (2022). Open Access Theses & Dissertations. 3539.