Pierre Mangeol

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Ribosomal (r-) RNA adopts a well-defined structure within the ribosome, but the role of r-proteins in stabilizing this structure is poorly understood. To address this issue, we use optical tweezers to unfold RNA fragments in the presence or absence of r-proteins. Here, we focus on Escherichia coli r-protein L20, whose globular C-terminal domain (L20C)(More)
A double-tweezer setup is used to induce mechanical stress in systems of molecular biology. A double strand of DNA is first stretched and the data is compared to precedent experiments to check the experimental setup. Then a short foldable fragment of RNA is probed; the typical unfolding/refolding hysteresis behaviour of this kind of construction is shown(More)
In order to mechanically unfold a single RNA molecule, an RNA/DNA hybrid construction is prepared which allows specific attachment to two micrometer-sized beads. A dual-beam optical trap thus holding the construct in solution captures the beads separately. Unfolding of a molecule is obtained by increasing the distance between the traps, one trap being(More)
In order to open the DNA double helix mechanically, a molecular construction is prepared which allows specific attachment of the two complementary strands of an individual molecule to two different μm-sized beads. The beads are separately captured by a dual optical trap, thus holding the DNA construction in solution. The opening of a molecule is obtained by(More)
Experimental studies of single molecule mechanics require high force sensitivity and low drift, which can be achieved with optical tweezers. We built an optical tweezer setup for force measurements in a two bead assay. A cw infrared laser beam is split by polarization and focused by a high numerical aperture objective to create two traps. The same laser is(More)
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