Sample Abstracts from Last Year’s Qualification Model
Sample Abstracts from Last Year’s Qualification Model Two abstracts from last year’s qualification model have been provided to help guide the team in the abstract writing process. The first abstract highlights the major components for inclusion in an abstract. You may want to provide your SMART Team practice in identifying these components on the second abstract. Saint Dominic School SMART Team Jacob Austin, Grace Gundrum, Grace Hilbert, Claire Hildebrand, Brigid Hughes, Sophia Jaskolski, Michael Kahler,William Klingsporn, Deidre Lagore, Katherine MacDonald, Tyler Mark, Jackson Minessale, Sean O'Brien, Matthew Peterman, Sam Reinbold, Alex Rusnak, Alex Sands, Lydia Scott, Rachel Storts, Mia Vuckovich, Michael Weisse, Nicholas (Mac) Wilke, Cade Wormington Teacher: Donna LaFlamme Ricin Comment [GRV1]: School and Team Member Names Comment [GRV2]: Advisor’s Name Comment [GRV3]: Title PDB: 2AAI Comment [GRV4]: PDB File Primary Citation: Rutenber, E., Katzin,B.J., Ernst, S., Collins, ElJ., Mlsna, D., Read, M.P., Robertus, J.D. (1991). Crystallographic refinement of ricin to 2.5 A. Proteins 10: 240-250. Comment [GRV5]: Primary Citation Abstract: In 1978, Bulgarian journalist and critic of communism, Georgi Markov, was assassinated on a London street by a probable KGB spy, who injected him with 0.2 mg of ricin, the lethal dose being less than 0.010 mg/kg. Ricin, a ribosome inactivating protein, can be extracted from the seeds of the castor oil plant (Risinus communis) where it functions as an insecticide. The Saint Dominic SMART Team modeled the heterodimeric protein ricin using 3D printing technology. Chain B of ricin binds to terminal galactose residues on cell surface glycoproteins and glycolipids of mammalian cells, facilitating ricin’s entry by endocytosis. The toxin then navigates a complex system of cytoplasmic membranes from early/late endosomes, to the trans-Golgi network, to the endoplasmic reticulum (ER). In the ER lumen, translocases are thought to move the toxin into the cytosol but it is not known if Chain A is activated by cleavage from Chain B before or after translocation. Once in the cytosol, Chain A irreversibly disables ribosomes by removing adenine 4324 from the 28S RNA strand of the large subunit. To do this, active site residues Tyr80 and Tyr123 are thought to stabilize A4324, while Arg180 and Glu177 hydrolyze the glycosidic bond attaching it to the sugar-phosphate RNA backbone. A4324 belongs to the highly conserved sarcin-ricin loop and its removal shuts down protein synthesis by preventing elongation factor binding. An intracellular terrorist capable of disabling 1500 ribosomes/minute, one molecule of ricin can kill a cell. Researchers are now developing immunotoxins incorporating ricin to target and assassinate cancer cells rather than people. Comment [GRV6]: “Big Picture” or “Hook” Statement Comment [GRV7]: Modeling Project Statement Comment [GRV8]: Structure/Function Description Comment [GRV9]: Tie to the opening “big picture” and description of “next steps” Sample Abstracts from Last Year’s Qualification Model Marquette University High School SMART Team J. Fuller, D. Kim, R. Sung, E. Arnold, A. Borden, L. Ortega, R. Johnson, H. Albornoz-Williams, C. Gummin, A. Martinez, N. Boldt, D. Ogunkunle, P. Ahn, B. Kasten, Q. Furumo, N. Yorke, J. McBride, I. Mullooly, M. Tripi, D. Hutt. Teachers: Keith Klestinski and Carl Kaiser Ricin—A Deadly Legume Extract PDB: 2AAI Primary Citation: Rutenber, E., Katzin,B.J., Ernst, S., Collins, ElJ., Mlsna, D., Read, M.P., Robertus, J.D. (1991). Crystallographic refinement of ricin to 2.5 A. Proteins 10: 240-250. Abstract: One of the most deadly toxins ever discovered comes from the waste of castor bean oil processing. The toxin, ricin, has been responsible for the deaths and attempted attacks of world leaders. Ricin is a protein molecule with two major chains—chain A and chain B. Chain A, acts as an enzymatic polypeptide that catalyzes the N-glycosidic cleavage of a specific adenine residue from 28S ribosomal RNA. The amino acids in the active site responsible for this action are Glu 177, Arg 180, Tyr 80, Tyr 123, Glu 177, Arg 180, and Trp 211. With help from chain B, the ricin binds to mammalian cell surfaces. A disulfide bond breaks between the two chains allowing only chain A to enter into the cell via endocytosis. Once in the cell, it delivers the catalytically active polypeptide into the cytosol where it irreversibly inhibits translational elongation, an important aspect of protein synthesis, at a rate of 1500 ribosomes per minute. Researchers are working to develop an immunotoxin that combines the targeting ability of an antibody with the toxicity of the ricin A chain. These antibodies are directed exclusively toward cancer cells to deliver a “lethal blow” ultimately destroying the cells. Cancer cell targeting and ricin’s unique ability to cleave important parts of ribosomes will be of continued interest in oncology research. In order to show the detailed complexities of the protein, the Marquette University High School SMART (Students Modeling A Research Topic) Team has modeled ricin using 3D printing technology.
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