Proteins act as macromolecular machinery that mediate many diverse
biological processes - the molecular mechanisms of this machinery has
fascinated biologists for decades. Analysis of the kinetic and
thermodynamic features of these mechanisms could reveal unprecedented
aspects of how the machinery function and will eventually lead to a
novel understanding of various biological processes. This dissertation
comprehensively demonstrates how two universally conserved guanosine
triphosphatases in the signal recognition particle and its membrane
receptor maintain the efficiency and fidelity of the co-translational
protein targeting process essential to all cells. A series of
quantitative experiments reveal that the highly ordered and coordinated
conformational states of the machinery are the key to their regulatory
function. This dissertation also offers a mechanistic view of another
fascinating system in which multistate protein machinery closely control
critical biological processes.
Written while completing graduate work at California Institute of
Technology.