This Fall 2008 semester we have a special interdisciplinary Watkins Visiting Professor, Dr. Don C. Lamb from Ludwig Maximilian University, Munich, Germany. He is a young new leader in biophysics, having received his Ph.D. from the University of Illinois Urban-Champaign, but is a native of Wisconsin who moved to Germany to take up the challenge of creating a new world class biophysics effort there. His research group uses fluorescence and single molecule methods to investigate the dynamics of functions of biomolecules. These methods are minimally invasive, can be performed in living cells, and provide direct insight into the mechanism of various biological processes. They are interested in developing and improving ultra-sensitive fluorescence methods, performing quantitative analysis and applying these methods to investigate biological systems.

 

Public Lecture: Hubbard Hall 209 September 11, 4 PM

Where the Biothings are: The world of Biophysics

Biophysics is one of the fastest growing fields in physics and spans a broad variety of topics from Structural Biology to Environmental Sciences. Historically, biology and physics have opposing approaches to science. Physicists derive and simply their problems whereas biologists investigate the complexity of living things and classify their observations.

In this talk, we will investigate how the disciplines of biology and physics join together in Biophysics to unravel the secrets of life. Biophysics emerged as an interdisciplinary field in the middle of the last century when many of the physicists involved in the development of Quantum Mechanics later turned their attention towards understanding biological processes. The synergies of Biophysics will be highlighted with a number of examples from recent experiments taken from the subfield of Molecular Biophysics.
 


Physics Seminar: Hubbard Hall 218, September 15, 4 PM

Using Fluorescence to Investigate the Cellular and Nano World
 

The habitants of the Nanoworld are single molecules, particles, and complexes. Fluorescence techniques have developed beyond the mere detection of these inhabitants to studying their behavior. In my talk, I will introduce some of these methods and describe their application with three examples.

In the first example, we used single pair Förster Resonance Energy Transfer (spFRET) and total-internal reflection fluorescence microscopy to investigate the dynamics of a naturally occurring nanomachine, the TATA-Box -Binding Protein (TBP). TBP is involved in gene transcription, the first step in protein biosynthesis. Upon addition of a second protein, negative cofactor 2 (NC2), the TBP-NC2 complex becomes mobile on the DNA and gene expression is repressed. This dynamics brings an entirely new perspective to the mechanistic understanding of gene repression. 

In the second example, we investigate the last step in protein biosynthesis: protein folding. Many proteins require the assistance of molecular chaperones to fold rapidly and efficiently. Using pulsed interleaved excitation (PIE) and spFRET, we have investigated the function of the chaperone protein, GroEL. Chaperone proteins are believed to aid protein folding by isolating the nascent polypeptide chain from deleterious interactions within the cell. Our investigations reveal a much more active role of the Chaperone protein, GroEL, in protein folding. GroEL actively stretches our substrate, the maltose binding protein, upon binding and controls the release of the substrate in the cavity of GroEL upon ATP and binding of the co-chaperone, GroES.

In the last example, single particle tracking is used to investigate the assembly and release of HIV particles. The main structural protein of HIV (GAG) has been fluorescently labeled with a green fluorescent protein. The kinetics of assembly are surprisingly fast, on the order of 200 s. Using the photoconvertable protein mEosFP, we have determined that initiation of the assembly site occurs from plasma-membrane bound GAG whereas further assembly comes from both plasma-membrane bound and cytosolic GAG molecules. By monitoring the mobility of the budding sites, we have also visualized virus release, which occurs on a significantly slower timescale than assembly: 1500 +/- 700 s.


Phys 600A Biophysics class: As part of Prof. Don C. Lamb's visit to Wichita State University as a visiting Professor of Physics and Biology he is teaching an intense short class on biophysics. Students may sign up for this class by contacting Prof. Nickolas Solomey, Physics Chairman at the Physics office listed below.