2002 Ameritech Projects

The P680 Reaction Center of Photosystem II

Kettle Moraine High School: Team I

Team Picture

Photo:Photosystem II Students:
Stacy Weber, Joe Yatzeck, Rebeca Buendia

Teacher: Pete Nielson

This photosynthesis model is of the P680 reaction center of photosystem II which collects photons of energy and boosts electrons to a higher energy level.

This protein model was chosen because it was felt that by seeing a model of the chlorophyll molecule p680 reaction center one could better explain the details of photosynthesis in the classroom. This model demonstrates that structure and symmetry directly relate to function as a series of chlorophyll molecules donate their photoexcited electrons to an electron transport chain. These electrons are passed to pheophytin and in turn to photosystem I. The four chlorophyll molecules and two pheophytin molecules are cradled in a symmetrical set of transmembrane alpha helices which also use four histidine residues to support a single atom of iron.

 

Aquaporin, a Water Transporter

Kettle Moraine High School: Team II

Team Picture

Photo:Aquaporin Students:
Eric Powleit, Chris Pinahs, Jacob Schmidt

Teacher: Karen DeBoer

An aquaporin is a transmembrane protein in plants and animals that allows water molecules to move into the cell's interior.

Aquaporin is a tansmembrane protein used in many cells including those of humans, which permits the passage of water molecules into the cell. The central feature permitting this is the hourglass-shaped pore created by several alpha helices. At the thinnest point in this structure, rests a pair of asparagine residues, which are able to use the water molecule's polar nature to restrict passage to one molecule at a time. This model can be used in a classroom setting, as it is relatively durable. Each color represents a different alpha helix, demonstrating how these formations are critical in maintaining molecular structure, giving students a physical representation of what previously was kept to theory and discussion.

 

Hyaluronate Lyase

Rufus King High School: Team I

Team Picture

Photo:Hyaluronate Lyase Students:
Kayla Bunge, Christina Vogel, Brendan Sperandio, and Peter Marino

Teachers: Keith Zeisse and Liz Substad

Streptococcus pneumoniae hyaluronate lyase is a pathogenic bacterial spreading factor that interacts with ascorbic acid.

Streptococcus pneumoniae hyaluronate lyase is one of the most common causes of infections of neonates in the United States. The researchers noted in the Med-Line article are Li S, Kelly SJ, Lamani E, Farraroni M, and Jedrzejas MJ. It is so serious that in many cases when the infection is not fatal, the patient may suffer from seizures,blindness, and/or mental retardation. This enzyme rapidly degrades hyaluronan in an unusual manner. It makes an initial random cut in a hyaluranan chain and moves quickly along the chain, while releasing unsaturated disaccharide units. Ascobic aqcid (vitamin C) has recently been shown to bind to this enzyme…and inhibit it. So...drink your orange juice.

 

SV40 Capsid Comple

Rufus King High School: Team II

Team Picture

Photo:SV40 Capsid Comple Students:
Mohammed Farhoud, Adam Carr, Laura Gerber

Teacher: Dean Dolence

This is the structure of one of seventy-two pentamers comprising the simian virus 40 capsid shell.

Simian Virus 40 (SV40) is one of the largest viruses whose structure has been determined at the atomic level. Thilo Stehle, Steven J Gamblin, Youwei Yan, and Stephen C Harrison are the researchers credited with the research on SV40 (Structure 4, 165-182, 1995). The virus is composed of 72 pentamers connecting to one another to form a sphere. The assembly of this virus is believed to be influenced by the calcium ions, pH and ionic strength of its surroundings. The structure of SV40 hasallowed researchers to analyze, in detail, the contacts between pentamers that direct its assembly and stabilize the particle.

 

F0 Subunit of ATP Synthase

Wauwatosa West High School

Team Picture

Photo:F0 subunit of ATP Synthase Students:
P.J. Buske, Katie Hargreaves, Ellie Schiedemayer, Jackie Schlutz

Teacher: Donnie Case

ATP Synthetase is a large protein used to catalyze the synthesis of the energy molecule, ATP. It is a complex molecule with three main parts, F0, F1 and g, each made from several protein subunits. The F0 is a cylinder of twelve hydrophobic alpha helices c subunits that tranverse a bilayer membrane. Hydrogen ions, moving down a concentration gradient, bind to the Asp61 carboxylate of the c subunits causing the F0 cylinder to rotate and act like a molecular carousel. A rod shaped g unit connects the F0 and the F1 units and also spins. The F1 is knob-shaped, protrudes from the membrane, is water soluble, but does not rotate. It consists of six alternating alpha and beta subunits that catalyze the formation of ATP.

 

Exo Enzyme S of Pseudominas Aeruginosa

Riverside University High School


Students:

Courtney Nelson, Maria Martinez, Abigail McGraw, Temitope Thompson

Teacher: Jeff Anderson

Team Joe used the computer program Rasmol and information pulled from the Protein Data Bank to construct a three dimensional model of the Exo enzyme S found in the bacteria Pseudominas aeruginosa.

We began the process of protein modeling by attempting to comprehend various articles from online sources which dealt with the bacteria Pseudomonas aeruginosa and its Exo enzyme S. From our studies we concluded that the enzyme is a GAP protein meaning that it is a GTP activating protein. It functions with Rac and Rho proteins to inhibit the cell from functioning by stopping vesicle traffic. We applied our understanding of the molecule to the construction of the N terminus on the Exo S that binds the Rac protein causing the breaking of GTP into a phosphate and GDP. To reach these ends, we downloaded the Rasmol file for Exo S and the information that came with it. We had to distinguish between hydrogen bonds and those added in to our altered downloaded version. Then we added the accessory bonds that formed between the various amino acids and monitor lines to stabilize the molecule. The molecule was built and, using the color code found on Rasmol, we painted our molecule to distinguish between different chains and termini.

 

Hydrogenase

Bay View High School

Team Picture

Photo:Hydrogenase Students:
Charles Radomski, Dinero Fudge, Chue Yang

Teacher: Dan Wexler

Fuel cells may one day be powered by hydrogen generated by bacteria in bioreactors.

Hydrogenases play a central metabolic role in various microorganisms. These enzymes catalyze the half-cell reaction 2H+/H2. The best studied of these is a heterodimeric protein from Desulfovibrio gigas. The enzyme active site is located in the large subunit and coordinates one atom each of nickel and iron. Hydrogen gas can be used to power fuel cells for the efficient and clean production of electricity. Currently, hydrogen is produced by the combustion of fossil fuels or through the use of solar battery-induced splitting of water. It has been known for some time that hydrogen can also be produced by certain algae and bacteria. If such biological methods could be adapted to bioreactors at high efficiency, they would provide low cost, environmentally friendly sources of hydrogen. These adaptations will depend on the ability of scientists to genetically engineer microorganisms to increase hydrogen production.

 

Alpha-Hemolysin

Brown Deer High School

Team Picture

Photo:Alpha-Hemolysin Students:
Matt Kopp, Matt Kuczynski, Emily Majusiak, Jon Kao, Shelly Samet, Matt Derosier, Ramon Smith, Nick Russell, Josh Belke, Ryan Kautzer

Teacher: Brian Fortney

We are researching the mechanism by which the a-Hemolysin protomer assembles into a heptamer, and produces a b-barrel that spans the cell's bilayer.

A current model that is being used for research into the Anthrax bacteria's mechanism of cell penetration is the mechanism that a-Hemolysin uses to produce a b-barrel. A single unit of the a-Hemolysin (called a protomer) attaches to the bilayer of a cell, and attracts six other protomers to form a heptamer. It is this heptamer that forms the transmembrane pore, which is called a b-barrel. The b-barrel is composed of fourteen strands of protein, with each protomer contributing two b-strands. It is this mechanism that is being used as a model for comparison of the Anthrax bacteria's mechanism. Our team will be describing the different parts of the a-hemolysin molecule, as well as the mechanism that each protomer uses to extend the two b-strands into the cell's bilayer.

 

DNA Helicase

St. Dominic Middle School

Team Picture

Photo:DNA Helicase Students:
Erin Dougherty, Meggie Fabiszak, Rachel Hartert, Laura Lauck, Nathan Leupold, Melissa MacDonald, Theresa Malone, Nick Merkt, Kate Picciolo, Sarah Scherrman, Emily Schultz, Mike Solberg, Monica Von Reuden, Joe Willis

Teacher: Donna La Flamme

The St. Dominic School Bio-molecular Modeling Team has designed a physical model of a bacterial RecG helicase whose structure has recently been published in Cell (October 5, 2001); this helicase uses its DNA unwinding ability to restart replication when it has been stalled by DNA damage.

Interest in Werner's Syndrome led our fourteen student team to search the Protein Data Bank for a helicase molecule to build. Sufferers of Werner's Syndrome have inherited two defective genes for the Werner helicase (one from each parent) and begin experiencing accelerated aging and increased cancer rates after adolescence. Helicases are important to cells because they unwind double-stranded DNA so that it can be repaired and replicated. Un-repaired DNA damage can lead to cancer. We chose RecG, whose structure was published in the October 2001 issue of Cell, because this particular helicase was the most interesting of those deposited in the Protein Data Bank. The scientists actually crystallized it bound to a stalled DNA replication fork and they used their structure to figure out how it probably works to restart replication when it has stopped due to DNA damage. All three models of RecG made by our team will be useful in the classroom because they can be used and reused to stimulate questions, and aid discussions and explorations of DNA structure, protein structure, protein function, DNA replication, and the molecular basis of diseases such as Werner's Syndrome.