The effects of crowder hydrophobicity on the populations of two conformations of XCL1

Jessica Teodoro
MSc Student 
Department of Biochemistry

Date: January 20, 2025
Time: 1:00 p.m. to 2:00 p.m. 
Room: CSF 1302

Abstract:

Classic Biochemistry studies protein structure in dilute solution. However, the inside and outside of cells where proteins are produced, folded, and eventually secreted, are highly concentrated with macromolecules, i.e. crowded. Most of the crowding studies so far use synthetic, supposedly inert molecules, while the macromolecules in real biological systems have non-covalent interactions, e.g. van der Waals forces or electrostatic interactions. XCL1 (Lymphotactin) is a chemokine protein. It is metamorphic and shifts between two distinct structures. Some conditions favour the XCL1 monomer, which has a mixed α and β secondary structure, while other conditions favour the dimer, which takes on an all β conformation. These two structures can be readily differentiated using nuclear magnetic resonance (NMR). My goal is to characterize the effects of crowder hydrophobicity on the balance between two XCL1 structures. Unlike previous work with XCL1 in artificial crowders, my work employs real, biological crowders in the form of mixtures of globular proteins. I will use two globular protein crowder mixtures with different hydrophobicities to probe the role of hydrophobicity in crowding effects on protein structure. Recombinant XCL1 is produced by Escherichia coli, purified, and investigated through NMR. The outcomes of this research will measure the effects of crowder hydrophobicity on protein structure in XCL1.