Integrated Calendar

We think of proteins as ensembles of several mutually-interconverting conformations, and therefore protein 'structure' actually refers to a weighted representation of all conformers contributing to protein behavior. Less intuitive yet very important is the fact that the biological function of proteins depends sometimes upon elusive minor conformers that might be overlooked by a superficial static view. This realization has pushed bio-NMR, a leading solution-based structural method, to the forefront of efforts to identify and, if possible, actually 'see' lowly-populated conformations. The ability of high-resolution NMR to follow and characterize these nearly invisible unsung heroes of protein function will be demonstrated using three case-studies from our research group, (i) intrinsically disordered proteins that challenge the fundamental structure-function dogma, (ii) an under-appreciated pH-dependent oligomerization domain, and (iii) inhibition of a potassium channel by a marine toxin. Together these examples highlight the versatility of solution NMR in illuminating the molecular basis of biological functions involving protein conformational flexibility.

The discovery of a very Standard-Model-like (SM) Higgs boson at the LHC has marked a major triumph for the Standard Model. However, there are appear to be non-SM phenomena in nature, such as Dark Matter, that would be explained only in a more general theory of nature. One way of probing the structure of such a theory is to search for an extension of the SM Higgs sector by directly looking for additional Higgs Bosons in nature. In this talk, I will review the most recent results from the ATLAS Experiment in the search for such bosons, with a focus on searches for a heavy neutral Higgs and an electrically charged Higgs boson.

A single colloidal particle trapped in an optical vortex experiences two optical forces: a gradient force confining it to motion along a finite width ring of light, and radiation pressure driving it along the perimeter of the ring. As a result, the particle rotates, at constant angular velocity with thermal fluctuations. When a second particle is introduces to the vortex trap the two particles pair due to a pseudo-potential caused by the interplay between hydrodynamic interactions and the curvature of the particles’ trajectory. We study the collective excitations of many colloidal particles driven in an optical vortex trap. We find that even though the system is overdamped, hydrodynamic interactions due to driving give rise to non-decaying excitations with characteristic dispersion relations. The collective excitations of the colloidal ring reflect fluctuations of particle pairs rather than those of single particles.