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Paul Wiggins

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I am currently a graduate student in physics working with the Rob Phillips group on biophysics. 

Office: 157 Broad
Phone: 626-395-3106
Email: pwiggins@its.caltech.edu

Personal page

Research in progress

Paper Archive

CV

Research

R. Phillips and I have proposed a simple physical model for the function of mechanosensitive ion channels in which membrane-protein interactions play a central role. We have shown that under membrane tension, these interactions lead to a picture analogous to a simple nucleation problem. These simple models can predict many of the experimental features of the MscL channel such as the dependence of the opening tension on the membrane environment and the nature of the channel substates.
We have proposed that in some biological contexts it is possible to deduce the forces applied to a membrane from its conformation, captured via cryo electron microscopy tomograms (three dimensional reconstructions). Our hope is that this indirect, noninvasive method of force measurement will provide insight into both structural questions (for example, see mitochondrial structure below) and functional questions such as the mechanics of viral budding and the growth of filopodia. This is an ongoing collaboration with E. Peterson, W. Klug, and G. Jensen.
Recent observation by T. Frey and others have revealed that the structure of the mitochondria is different from the cartoons pictured in the biology books for 40 years! We have been applying membrane physics to analyze the mitochondrial structure in an attempt to explain the observed configuration as a constrained mechanics problem. This is an ongoing collaboration with P. Purohit, R. Phillips, & J. Kondev.
Recent cyclization experiments by T. Cloutier & J. Widom have revealed that highly curved DNA is significantly easier to bend than predicted by current theoretical models. R. Phillips, P. Nelson, and I propose a modification to the wormlike chain theory which introduces a bend softening due to localized buckling. This new theory can account for the observed softening while leaving most features of the theory unchanged and therefore consistent with precise DNA force extension measurements. Many of the results in this new theory can be derived exactly. The recent experiments of T. Cloutier & J. Widom have also provided additional evidence for significant sequence dependence in the persistence length of DNA. We are also working on understanding sequence dependence effects as well as collaborating with A. Berglund on single molecule DNA mechanics experiments.
Ongoing experimental work examining the simplest molecular motors.

Publications

Education