"Protein Structure and Function: Insights from Antifreeze Proteins and the Polar Organizing Protein Z"
Speaker: Dr. Krisztina Varga, Associate Professor, University of New Hampshire
Day and Date: Friday, September 6th, 2024
Time: 10:45-11:45 AM
Location: HST L185
Abstract:
Effective cryoprotection is an important unsolved practical problem in the pharmaceutical and food industries, agriculture, and medicine despite considerable advancements in the past decades. Nature employs a variety of compounds and strategies for freeze avoidance and freeze tolerance that enhance the survival of organisms in extreme cold environments. One of these strategies, antifreeze proteins (AFPs) have evolved over millions of years. AFPs are produced in cold adapted organisms and contribute to the organisms’ freeze avoidance or their ability to survive freeze/thaw cycles. The goal of this project has been to investigate the mechanism by which antifreeze proteins protect against the damage typically inflicted by the cold, including the underlying molecular mechanism of ice-binding. Here we are presenting structural and functional characterization of an antifreeze protein, ApAFP752 from the desert beetle Anatolica polita, and we are also highlighting applications of this protein. A better understanding of antifreeze proteins can guide the design of advanced cryofunctional materials, including engineered antifreeze proteins and synthetic biomimetic cryo-active materials (e.g., polymers) inspired by natural cryoprotectants, to effectively prevent ice formation and protect biological systems during low-temperature storage, thereby enhancing the preservation of cells, tissues, and organs.
The second half of the talk will focus on Polar Organizing Protein Z (PopZ) in Caulobacter crescentus, which is a bacterial hub protein and forms polymeric scaffolds at cell poles, essential for recruiting regulatory proteins from the cytoplasm. While most proteins interact with one or only a few other proteins, a relatively small number of proteins act as ‘hubs’ and can bind a very large number (~10-100) of protein partners, often called ‘one-to-many binding.’ Intrinsic disorder is a common feature of hub proteins, which is characterized by a prominent lack of ordered tertiary structure. Using solution NMR spectroscopy, we have investigated PopZ's interactions and structurally characterized a truncated, monomeric version of PopZ that remains soluble and fully capable of binding its targets. These findings enhance our understanding of how hub proteins can be promiscuous yet maintain specificity for specific client proteins.
Personal Bio:
Krisztina Varga is an Associate Professor in the Department of Molecular, Cellular & Biomedical Sciences at the University of New Hampshire. She earned her Ph.D. in Chemistry from Columbia University and completed postdoctoral fellowships at the University of Oxford (UK) and the University of Colorado at Boulder. She began her academic career as a faculty member at the University of Wyoming before joining the University of New Hampshire in 2016. Her research program uses NMR spectroscopy and other biophysical methods to investigate protein structure-function relationships of biomolecules. Her recent research projects include antifreeze proteins, chiral nanomaterials, the bacterial hub protein PopZ, the photoreceptor phosphodiesterase-6 (PDE6), and a viral protein from SARS-CoV-2.
This event is free and open to the public. Please reach out to the Department of Bioengineering's team (inbioe@lehigh.edu) with any questions or comments.