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Undergraduate Researchers

Elizabeth Plum, Biochemistry and Molecular Biology

Aggregation of Potential Drug Delivery Vehicle
Faculty Mentor: Dr. Richard Karpel

Rattlesnakes are well known for their poisonous bites but surprisingly, the venom of the South American rattlesnake Crotalus durissus terricus, possesses a valuable protein called crotamine. This protein is a 42- residue polypeptide with unusual properties not known to other toxins. It is a cell penetrating protein (CPP) and once inside cells, it localizes on chromosomes. Crotamine is not only able to penetrate, but is also a transporter, able to carry small molecules or even entire genes into cells. For example, it has been previously shown that crotamine facilitated the transfection of plasmid DNA into mice bone marrow. Crotamine specifically enters only actively proliferating (AP) cells through an interaction with heparin-glycosaminoglycans (GAG). It forms ternary complexes with these GAGs and DNA. Crotamine is able to bind to negatively charged DNA because it is highly basic, containing 9 lysine and 2 arginine residues. Crotamine-DNA complexes then enter the cell by endocytosis and localize on the nucleus. Past experiments I have carried in the laboratory have shown that heparin can break up these aggregates and now I seek to characterize both crotamine-DNA and crotamine-GAG aggregates. Researchers have demonstrated that the internalization of these peptides is dependent on the size of the complex, signifying that different aggregate sizes have different transfection efficiencies. Therefore, the rate of endocytosis is dependent on the size of these aggregates and the optimum size will lead to better gene delivery. Because crotamine carries DNA into the cell in aggregated form, the characterization of these complexes is extremely important for understanding of this cell penetrating protein. The purpose of this research is to determine the conditions under which these aggregates form and the size of these aggregates, including the hydrodynamic radii.

How did you find your mentor for this project?

I took biochemistry with Dr. Karpel in the fall of 2008 and then I approached him and asked him if there was space for me to work in his lab.

How did you know this was the project you wanted to do?

I find it extremely interesting! I work with snake venom that could one day be used to penetrate cells and deliver small molecules.

How much time do you put into it?

I usually go to the lab a couple times a week. It just depends on what needs to be done on that particular week.

How did you hear about the Undergraduate Research Award program?

I think I saw posters for it. Then I talked to my mentor about it.  

What academic background did you have before you started?

I have done research before at NIH.

Was the application difficult to do?

Not at all. It actually helped me to sort my thoughts out about the project.

How much did your mentor help you with this?

If I had any questions, he was willing to answer them.

What is your advice to other students about getting involved in research? 

Do it! It is such a great opportunity! It is the experience of a lifetime.

What are your career goals?

I have no clue at this moment. Maybe pharmacy school, maybe medical school. Only God knows!

What has been the hardest part about your research?

The hardest part is definitely putting time into it. I have to manage my time really well between studying, working two part-time jobs, and research.

What was the most unexpected thing?

The most unexpected thing, which was also the coolest thing, is that venom from the snakes that we research on actually comes from Brazil, which is where I am from!

How does your research relate to your work in other classes?

It relates to pretty much everything! I am always applying something that I learn in class, whether it is to make a solution, run an electrophoresis gel, or growing cells.