Degree Type
Honors Capstone Project
Date of Submission
Spring 5-1-2019
Capstone Advisor
Ivan Korendovych
Honors Reader
Melissa Pepling
Capstone Major
Biology
Capstone College
Arts and Science
Audio/Visual Component
no
Capstone Prize Winner
no
Won Capstone Funding
no
Honors Categories
Sciences and Engineering
Subject Categories
Biology | Life Sciences
Abstract
Positron Emission Tomography and Magnetic Resonance Imaging, two of the most clinically important imagining techniques, often rely on the ability to bind lanthanide ions with high affinity. Small, non-immunogenic metal-binding proteins with a high affinity for lanthanides have been highly sought out for such purposes due to low likelihood for immunogenicity, versatility, and ease of modification3 . However, despite much effort the problem of creating proteins for specific and selective binding of lanthanides a la carte has not been solved. Our approach is to engineer catalytic sites into existing metal-binding proteins to link metal binding to a straightforward spectroscopic readout. Calmodulin (CaM), a eukaryotic messenger protein, binds Ca2+ through its EF-hands, initiating a conformational change that forms an active site for substrate binding1 . Previous experiments within the Korendovych lab converted CaM into AlleyCat7, a highly efficient enzyme for Kemp elimination, a reaction that can be followed visually2 . Here we report that by strategically introducing two mutations into AlleyCat7, it can be converted into a selective binder of lanthanides. The resulting protein, named HollEE, is at least 10,000-fold more selective for lanthanides as compared to Ca2+, an ion normally present in blood at high concentrations. We are particularly interested in yttriumbinding properties of HollEE, due to importance of 90Y as a theranostic nucleus for treatment of Hepatocellular Carcinoma (HCC). In addition to biomedical applications HollEE can serve as a biocompatible, catalytically-amplified sensor for metal ions.
Recommended Citation
Gigon, Alaine, "Modification of Calmodulin EF Hands for Rare Earth Metal Selectivity" (2019). Renée Crown University Honors Thesis Projects - All. 1344.
https://surface.syr.edu/honors_capstone/1344
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