Marie-Eve Aubin-Tam

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All cells employ ATP-powered proteases for protein-quality control and regulation. In the ClpXP protease, ClpX is a AAA+ machine that recognizes specific protein substrates, unfolds these molecules, and then translocates the denatured polypeptide through a central pore and into ClpP for degradation. Here, we use optical-trapping nanometry to probe the(More)
ClpXP and other AAA+ proteases recognize, mechanically unfold, and translocate target proteins into a chamber for proteolysis. It is not known whether these remarkable molecular machines operate by a stochastic or sequential mechanism or how power strokes relate to the ATP-hydrolysis cycle. Single-molecule optical trapping allows ClpXP unfolding to be(More)
Although nanoparticle-protein conjugates have been synthesized for numerous applications, bioconjugation remains a challenge, often resulting in denaturation or loss of protein function. This is partly because the protein-nanoparticle interface is poorly understood, which impedes the use of nanoparticles in nanomedicine. Although the effects of nanoparticle(More)
Aptamer and antibody mediated adhesion is central to biological function and is valuable in the engineering of "lab on a chip" devices. Single molecule force spectroscopy using optical tweezers enables direct nonequilibrium measurement of these noncovalent interactions for three peptide aptamers selected for glass, polystyrene, and carbon nanotubes. A(More)
We report the effect of nanoparticle ligand charge on the structure of a covalently, site-specifically linked protein. Au nanoparticles with positive, negative, and neutral ligands were appended to a specific cysteine, C102, of Saccharomyces cerevisiae cytochrome c. Conjugates were purified by HPLC or gel electrophoresis. Circular dichroism spectroscopy(More)
Departments of Mechanical Engineering and Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts AVenue, Cambridge, Massachusetts 02139, CNR-INFM, Laboratorio Nazionale TASC BasoVizza, 30142 Trieste, Italy, Department of Chemical and Biomolecular Engineering, UniVersity of PennsylVania, Philadelphia, PennsylVania 19104, and(More)
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