"Poking" Proteins with Sharp Needles: Biophysical Insights via Force Microscopy

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Date/Time:Monday, 10 Nov 2014 from 4:10 pm to 5:00 pm
Location:Physics 0003
Phone:515-294-5441
Channel:College of Liberal Arts and Sciences
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Gavin King University of Missouri

Abstract: Single-molecule imaging and force spectroscopy studies have produced rich insights into macromolecular structure and dynamics in biological settings and the atomic force microscope (AFM) has thus emerged as an important complementary apparatus in the structural biologist's toolkit. While conventional AFM has achieved sub-nm resolution imaging of membrane proteins in native membrane, atomic-scale tip-sample stability - which opens promising new avenues of AFM study - has previously only been achieved in highly isolated non-biological environments (i.e., cryogenic temperatures, ultra-high vacuum). We adapted techniques originally developed by the optical trapping microscopy community, and have constructed an ultra-stable AFM in which the tip and the sample positions are independently measured by, and stabilized with respect to, a pair of laser foci in three dimensions. Recently, we extended ultra-stable AFM to common biological imaging conditions (tapping mode in aqueous buffer solution) and have exploited the local observation of three dimensional (3D) tip trajectories to yield 3D interaction force components in a direct manner. In this talk I will discuss these developments in the context of addressing central questions in membrane biophysics. In particular, using AFM we have begun to shed light on the dynamic structure of SecYEG and other central components of the general secretory system of E. coli.

Bio: King received his PhD in Physics from Harvard developing solid-state nanopore technology for molecular sensing applications wtih Jene Golovchenko and Daniel Branton. He went onto JILA (University of Colorado/National Institute of Standards and Technology) for postdoctoral research with Thomas Perkins focusing on precision biophysical measurements. He has been a faculty member in Physics and Biochemistry at the University of Missouri since fall 2009.