Esra Ayan, Koç University 

Abstract:

Streptavidin biotin binding is a paradigm system for better understanding the dynamics of multimeric protein complexes and investigating both intramolecular and intermolecular interactions. Streptavidin-biotin binding is the strongest interaction observed between a protein and its prosthetic group. Streptavidin-biotin system is also the most well studied and has some of the broadest applications in biotechnology. It is imperative that to understand this interaction in real time so that we can capture the important and very short-lived binding interactions of this paradigm system. This will enable refinement of existing kinetic models and development of unique biotechnological applications. Here we present three high-resolution structures of the apo- and holo-streptavidin at both ambient (Apo-SFX, 1.7 Å, Linac Coherent Light Source) and cryogenic temperatures (Apo-Cryo, 1.1 Å, SSRL; Holo-Cryo, 1.5 Å, Turkish DeLight homesource XRD) obtained from the different radiation sources. To investigate intramolecular structural properties and the dynamics of the three structures, cross correlation (GNM – Gaussian Network Model) were applied and compared. We highlighted the conformational changes of the three structures which were obtained experimentally in this work are correlated with the previous computational works. Also, atomic displacements of the (B-Factor values) structures were presented. Specific radiation damages were calculated using B-factor values via RABDAM program. We concluded that the SFX gave the best performance due to the ultrashort X-Ray/protein interaction time, where less temperature was deposited onto the protein structure, resulting in less radiation damage. Accordingly, this study validates a novel streptavidin cooperative allostery that mimics the substrate biotin by binding to the substrate via water molecules providing a polar interaction network as well as identifying and verifying the accuracy of previous streptavidin structures, the SFX approach will provide structural data without temperature or radiation damage, providing a robust template for future studies.

Poster Session Link: https://gather.town/invite?token=0pEoq7VP

If you have any questions for the presenter, please contact them via email: esraayan20@ku.edu.tr