Recorded Student Oral Presentations

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Purification of Viral Fibroblast Growth Factors Tagged with Maltose Binding Protein using Cationic Starches Derived from Maize

Korey Brist

College of Science & Engineering


Tagging proteins of interest with maltose binding protein (MBP) is a common method to produce recombinant proteins in E. coli that can be purified using amylose resin in affinity chromatography with a high degree of purity. The rising price of amylose resin over the years has made this purification method less desirable. Successful methods for purifying MBP-tagged proteins have previously been demonstrated using Catamyl-VS cationic starch derived from tapioca. While this method seems to offer an affordable route for protein purification, finding a cationic starch derived from tapioca starch that meets the specifications of Catamyl-VS has proven itself impossible due to its low demand in the paper making industry here in the United States. This study aims to find a cationic starch derived from corn that is cost effective, readily available in the market, and successful in purifying MBP tagged proteins with a high degree of purity.

Four cationic starches derived from corn (Charge +99, Charge +110, Charge +309, Charge +310) were kindly gifted to us by Cargill. Prior to this study, viral fibroblast growth factor (vFGF) genes from Autographa californica M nucleopolyhedrovirus (AcMNPV) and Choristoneura fumiferana M nucleopolyhedrovirus (CfMNPV) were cloned with a coding sequence for MBP to produce plasmids coding for the fusion proteins Ac6 and Cf6, respectively. Ac6 and Cf6 plasmids were transformed into E. coli ER2508 to express the recombinant proteins. Lysate from Ac6 and Cf6 were incubated with each cationic starch at concentrations of 0.2%, 0.3%, and 0.4% (w/v) cationic starch. Precipitation was done with 10% (w/v) PEG 3350 and 50mM CaCl2. The bound MBP tagged protein was eluted off the cationic starch polymer by resuspension in 1M NaCl and separated by centrifugation. Current Bradford results show protein concentrations as high as 232µg/mL for Cf6 lysate with 0.4% (w/v) +309 cationic starch, and 311µg/mL for Cf6 lysate with 0.3% (w/v) +310 cationic starch. The Cf6 lysate with +99 and +110 cationic starches did not fall within the linear range of the BSA standard. A duplicate purification using Ac6 lysate and only +310 and +310 revealed high protein concentration in a Bradford assay, but high protein concentrations in the “No Starch” control as well. SDS-PAGE Coomassie Staining of both purification tests revealed no purification of the MBP-tagged vFGF protein and high protein precipitation in the no starch control. A lower percent PEG (6%) and lower protein concentrations were determined to run the experiment one more time to determine if we can eliminate the precipitation of unwanted proteins and purify the MBP-tagged vFGF protein. This purification is currently underway and will be followed by protein analysis, SDS-PAGE Coomassie staining, and Western Blotting. If successful, a comparison of the cationic starch purification will be compared to purification by amylose affinity chromatography. If the purification is high, I plan to continue researching the mitogenic effect vFGF has on insect and mammalian cells lines.

Stamp of Action

Kennedy Pierre-Toussaint

College of Liberal Arts


Stamp of Action
Kennedy Pierre-Toussaint
Chun Lok Mah
This stamp was created to represent the stamp of action mission; Where we motivate each other to fight injustice.
We currently live in a society that is unjust with the amount of inequality we are still facing today. Every instance of injustice that we see daily has organizations that emphasize the importance of their issue. I am creating a way to help identify and support those injustices but in a way, that other organizations would want to join and be a part of them. Not taking away from the injustice itself but highlighting those who share equal importance in building a connection. The goal is to work alongside these other organizations never against them. To represent this in the best way, I took inspiration from the first graphic commonly used as a symbol of resistance. I wanted to include the essence of change and growth in this logo, for this, I chose the butterfly. Then combined the two to create an abstract butterfly with the wings depicted as fists. This stamp is meant to create action and identify where the action is needed to be taken. Creating something that can be identified as a universal symbol for acknowledgment and change.
This project is meant to have an impact on the community in which it used to bring together all different types of individuals together. Two trial runs took place in the Spring of April 2021 in Winona, MN. I participated in two different protests one for Black Lives Matter and the other to prevent the building of a new juvenile detention center. During the first trial run, I distributed informational stickers that have a short description of the project along with a takeaway sticker of the logo. These cards stated “This stamp represents the action being taken to counter any issue of injustice that we are constantly facing in society. Those who wear this stamp symbolize their allegiance to progressive change and to improving the world we live in for equality”. For the second trial run buttons were handed out that depicted the logo and slogan, “where we motivate each other to fight injustice.