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Title: Single-molecule thiol-disulfide interchange
Author: Qing, Yujia
ISNI:       0000 0004 7966 2639
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2018
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Thiol-disulfide interchange occurs widely in cellular processes including redox sensing and homeostasis, protein folding, cell signalling, and the regulation of apoptosis. Nature exploits this chemistry in a highly selective manner, which is challenging to recapitulate in vitro. In this thesis, we report site selective and regioselective thioldisulfide interchange on macromolecular disulfide substrates elongated within a protein nanoreactor, where they react with cysteine thiolates presented at different locations along the length of a β strand. Numerous individual reaction events were detected by promoting the substrate turnover. For each substrate, we defined the most reactive cysteines on the β strand and which sulfur atom in the disulfide was attacked and found that the chemistry can be controlled with atomic precision. We further applied our control over the selectivity of thiol-disulfide interchange to the development of a molecular machine. Intrigued by technological potential, scientists have long attempted to control molecular motion. We monitor the individual 0.7-nm steps of a single molecular hopper as it moves in an electric field along a track in a nanopore controlled by a chemical ratchet based on thiol-disulfide interchange. The hopper demonstrates characteristics desired in a moving molecule: defined start- and end-points, processivity, fuel autonomy, directional motion and external control. The hopper is readily functionalized to carry cargos. For example, DNA can be ratcheted along the track in either direction, a prerequisite for nanopore sequencing.
Supervisor: Bayley, John Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available