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Full-Text Articles in Other Biochemistry, Biophysics, and Structural Biology

Supercharged Models Of Intrinsically Disordered Proteins And Their Utility In Sensing, Peter J. Schnatz Sep 2018

Supercharged Models Of Intrinsically Disordered Proteins And Their Utility In Sensing, Peter J. Schnatz

Dissertations, Theses, and Capstone Projects

In this thesis I show that greatly increasing the magnitude of a protein’s net charge using surface supercharging transforms that protein into a ligand-gated or counterion-gated conformational molecular switch. To demonstrate this I first modified the designed helical bundle hemoprotein H4 using simple molecular modeling, creating a highly charged protein which both unfolds reversibly at low ionic strength and undergoes the ligand-induced folding transition commonly observed in signal transduction by intrinsically disordered proteins in biology. Due to the high surface charge density, ligand binding to this protein is allosterically activated by low concentrations of divalent cations and the polyamine spermine. …


Identification Of Regions Responsible For The Open Conformation Of S100a10 Using Chimaeric S100a11/S100a10 Proteins, Liliana Santamaria-Kisiel Dec 2010

Identification Of Regions Responsible For The Open Conformation Of S100a10 Using Chimaeric S100a11/S100a10 Proteins, Liliana Santamaria-Kisiel

Electronic Thesis and Dissertation Repository

S100A11 is a dimeric, EF-hand calcium-binding protein. Calcium binding to S100A11 results in a large conformational change that uncovers a broad hydrophobic surface used to interact with phospholipid-binding proteins (annexins A1 and A2), and facilitate membrane vesiculation events. In contrast to other S100 proteins, S100A10 is unable to bind calcium due to deletion and substitution of calcium-ligating residues. Despite this, calcium-free S100A10 assumes an “open” conformation that is very similar to S100A11 in its calcium-bound state (Ca2+-S100A11). To understand how S100A10 is able to adopt an open conformation in the absence of calcium, seven chimeric proteins were constructed where regions …