Biophysical Society Newsletter | October 2017

6

2017

BIOPHYSICAL SOCIETY NEWSLETTER

OCTOBER

Publications BJ – Know the Editors Elsa Yan Yale University

vibrational spectra can be used similarly to circular dichroism spectra for characterization of protein secondary structures. The observed vibrational spectra are generated from protein backbone without the use of spectroscopic labels. The spectra are obtained using chiral sum frequency generation spectroscopy. This nonlinear vibra- tional spectroscopy is sensitive only to molecules at interfaces but not molecules in bulk solution. Hence, the vibrational signals are not interfered by background signals of solvent and other solute molecules in solution. Moreover, the signals provide information about orientation of proteins at interfaces. Therefore, the discovery has implica- tions in addressing problems related to proteins at interfaces. For example, my group has used the spectroscopic method to monitor aggregation of an amyloid protein on a membrane surface and observed conformational changes of the protein from disordered structures to alpha-helix and then beta-sheet. Other biophysicists have started using these vibrational signatures to tackle fundamental problems, including protein folding at inter- faces and ultrafast dynamics of energy propaga- tion along protein backbones. These vibrational signals can potentially be used in other areas, such as characterizations and design of biosensors, engineering of protein surfaces, and functional studies of membrane proteins (e.g., immunologi- cal response, cell adhesion, and transmembrane molecular transport). Congratulations to Four Young Investigators The Biophysical Journal sponsors awards for deserving students and postdocs who present post- ers at the Biophysical Society thematic meetings. Congratulations to four young investigators who were recognized for their science and presentation of their posters at the August 2017 meeting, Con- formational Ensembles from Experimental Data and Computer Simulations . Each received a certificate and $250.00.

Editor, Cell Biophysics

Elsa Yan

Q. What have you read lately that you found really interesting or stimulating? (a paper, a book, science or not science) Recently, I have been reading research articles related to proteins that can be found in biofilms. These types of proteins are considered to be Janus particles. Each of these proteins has a hydrophobic domain and a hydrophilic domain. Thus, they are strongly amphiphilic and surface-active. In their 2013 article in PNAS, Hobley et al. presented a striking image of a representative member of these proteins — biofilm surface layer protein A (BslA). To take the image, they ejected a droplet of BslA aqueous solution (40 microliter) into an oil phase and then reduced the volume of the droplet (by 5 microliter). The image shows the droplet of BslA solution before and after reduction of volume, where a spherical droplet becomes a drop shape (with a pointy end in its upper side) with a win- kled surface. The winkled surface looks like a plas- tic shopping bag holding a few liters of water in it. The image vividly demonstrates that BslA self- assembles into robust membrane-like structure at the water-oil interface and this structure can with- hold strong mechanical force. This fascinating image has prompted me to ponder how beautiful and delicate the molecular mechanism could be behind the formation of such sturdy macroscopic structures by individual protein molecules. Q. What has been your most exciting discovery as a biophysicist? My most exciting discovery as a biophysicist is to find that various protein secondary structures give signature nonlinear vibrational spectra. These