Teaching Unit Title: Structure and Function of Infectious Proteins
Developers: John Lukesh and Kristin Jenkins
Date: Bio 100, Fall 2013
Topics: Structure and function, proteins, chemistry, biochemistry, interdisciplinary science,
communication and collaboration, science and society
Level: Introductory biology, chemistry, or biochemistry for college and upper level high school students
Class Structure: The power point presentation was designed for a large lecture while also incorporating
active learning and student participation. The discussion activity developed for this lecture is suitable for
a small discussion section of 20–30 students.
Overview: In this activity, students will work in pairs (or groups of three) to answer a series of questions
about prions, while developing a protocol for hunters in Wisconsin to ensure the deer meat they
consume will not contain infectious prion proteins.
Learning goals and outcomes: Students will be introduced to protein structure and function, and in
particular, how structure is imperative for proper function. Students will also be introduced to protein
structure hierarchy and the noncovalent interactions that govern their three-dimensional shpae.
Description: In lecture, students learned about an infectious disease caused by a protein (PrPC) in a
misfolded form (PrPSc). This invariably fatal infection can be transmitted by coming into contact with the
misfolded protein. In Humans, variant Creutzfeldt-Jakob disease (vCJD), is believed to be closely related
to mad cow disease and can be acquired from consuming contaminated beef. Unfortunately, other
animals such as deer and elk, are known to carry a deadly prion disease known as chronic wasting
disease (CWD). This is especially worrisome in states such as Wisconsin and Minnesota where deer
hunting is popular. In this activity, students will work in pairs (or groups of three) to answer a series of
questions about prions, while developing a protocol for hunters in Wisconsin to ensure the deer meat
they consume will not contain infectious prion proteins.
Unit timeline: 50 minute lecture (30 minutes of lecturing with 15–20 minutes of class
participation/active learning) and 50 minute discussion activity.
Student Materials: In discussion, students will work in groups of 2–3, but each student will turn in their
own discussion activity worksheet.
Instructor Materials:
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5 min-course logistics
5 min-introduction to assignment,
25-30 min work on assignment
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10 min-wrap-up/go over general precautions listed on the chronic wasting disease alliance
website (below). Give students additional resources/websites with information on chronic
wasting disease in Wisconsin.
Weight loss over time, listlessness, lowering of the head, and nervousness are the most obvious signs
of chronic wasting disease in cervids
Chronic wasting disease among free-ranging cervids by county, United States, August 2012
Scenario: You work for the department of natural resources and receive a phone call from a local deer
hunter in Wisconsin who's planning on hunting this upcoming season, but has heard some talk on the
news about chronic wasting disease in Wisconsin deer herds.
Deer Hunter: "Hello, I plan on participating in the upcoming deer hunting season in Wisconsin but I've
heard some grumblings online and in the news about chronic wasting disease or CWD. This will be my
first year hunting and I'm not very familiar with this. Can you please tell me a little bit more about it?
What exactly is CWD and how can you tell if a deer has it? Are there any physical signs?
Response: Chronic Wasting Disease (or CWD) is a transmissible spongiform encephalopathy (TSE), or
prion disease in cervids (mule deer, white-tailed deer, elk, and moose). The infectious agent is a
misfolded prion protein (PrPSc). Prions are not actually alive, but like viruses they can reproduce on
their own by hijacking living cells. Like all prion diseases, CWD is invariably fatal. The most obvious
signs of chronic wasting disease in cervids are: weight loss, listlessness, lowering of the head, and
nervousness. You can also get your deer sampled for CWD testing. DNR will test it free of charge.
Many veterinary clinics throughout the state will sample deer for CWD testing.
Deer Hunter: This sounds pretty rare. Are similar diseases found in humans or other mammals? Is it
transmissible?
Response: Yes. Scrapie in sheep and goats, bovine spongiform encephalopathy (mad cow disease) in
cows, Creutzfeldt-Jakob Disease (CJD), fatal familial insomnia, and Kuru in humans. The disease is also
known to affect mink (transmissible mink encephalopathy) and cats (transmissible feline
encephalopathy) as the prion protein (PrPC) is well conserved among most mammals. CWD is highly
transmissible between cervids. Although the protein tends to accumulate in the brain and spinal
tissue, it can be found in virtually all tissue. It can even be found in blood, saliva and feces. CWD
transmission to humans has not yet been reported, but it is always better to be safe than sorry!!!
Deer Hunter: I plan on hunting mostly in and around Dane county (south central Wisconsin). Are there
known cases of CWD in this area? Do you recommend any other areas where it would be safer to hunt?
Response: Yes. The CWD management zone is located throughout south central Wisconsin which
includes Dane county. There have not been any confirmed cases of CWD in north central and north
eastern Wisconsin.
Deer Hunter: I actually have a bit of a science background and I know that proteins tend to be thermally
unstable. I will make sure to cook my deer meat at a very high temperature. I'm assuming this will
protect my family and I from acquiring this deadly disease.
Response: Unfortunately cooking meat at high temperatures doesn't denature the misfolded protein.
PrPSc is extremely stable, making it nearly impossible to denature the fibrous protein aggregates. They
are resistant to almost all denaturation processes including heat.
Deer Hunter: That's incredible! Why are these misfolded proteins so stable?!
Response: PrPSc proteins are much higher in β-sheet content than native PrPC. This causes the protein
to form insoluble aggregates of tightly packed β-sheets, held together by many noncovalent
interactions (H–bonding). This is an unfortunate example of how these relatively weak forces can add
up to something quite significant. You can also bring up the gecko example from lecture.
Deer Hunter: Is there anything I can do to sanitize my utensils and counters after processing the meat?
Response: It is recommend that you thoroughly clean and sanitize work equipment and work areas
with bleach after processing. Wipe down counters with 50/50 solution of household chlorine bleach
and water, and let them air dry.
The World Health Organization recommends the following procedure for the sterilization of all heatresistant surgical tools to ensure they are not contaminated with Prions:
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Immerse in a pan containing 1 N NaClO (20,000 parts per million chlroine) and heat in a
gravity-displacement autoclave at 121 °C for 30 minutes.
Deer Hunter: Thanks for all your help! My last question has to do with proper disposal of brain and
spinal tissue from the deer. I've always been told to dispose of it in a landfill. Could this be problematic
and potentially spread the disease to other animals? Do you have any other suggestions?
Response: With this being a transmissible disease one would think that you would want to dispose of
the brain and spinal tissue in an area that wouldn't be frequented by other animals (cyotes, cats,
racoons, etc.). Encourage the students to come up with alternative options.
Student Materials:
Weight loss over time, listlessness, lowering of the head, and nervousness are the most obvious signs
of chronic wasting disease in cervids
Chronic wasting disease among free-ranging deer by county, United States, August 2012
Scenario: You work for the department of natural resources and receive a phone call from a local deer
hunter in Wisconsin who's planning on hunting this upcoming season, but has heard some talk on the
news about chronic wasting disease in Wisconsin deer herds.
Deer Hunter: "Hello, I plan on participating in the upcoming deer hunting season in Wisconsin but I've
heard some grumblings online and in the news about chronic wasting disease or CWD. This will be my
first year hunting and I'm not very familiar with this. Can you please tell me a little bit more about it?
What exactly is CWD and how can you tell if a deer has it? Are there any physical signs?
Response:
Deer Hunter: This sounds pretty rare. Are similar diseases found in humans or other mammals? Is it
transmissible?
Response:
Deer Hunter: I plan on hunting mostly in and around Dane county (south central Wisconsin). Are there
known cases of CWD in this area? Do you recommend any other areas where it would be safer to hunt?
Response:
Deer Hunter: I actually have a bit of a science background and I know that proteins tend to be thermally
unstable. I will make sure to cook my deer meat at a very high temperature. I'm assuming this will
protect my family and I from acquiring this deadly disease.
Response:
Deer Hunter: That's incredible! Why are these misfolded proteins so stable?!
Response:
Deer Hunter: Is there anything I can do to sanitize my utensils and counters after processing the meat?
Response:
Deer Hunter: Thanks for all your help! My last question has to do with proper disposal of brain and
spinal tissue from the deer. I've always been told to dispose of it in a landfill. Could this be problematic
and potentially spread the disease to other animals? Do you have any other suggestions?
Response:
Supplementary Materials: http://www.knowcwd.com/
http://dnr.wi.gov/topic/wildlifehabitat/regulations.html
General precautions listed on the chronic wasting disease alliance website
General Precautions
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Do not eat the brain, eyes, spinal cord, spleen, tonsils, or lymph nodes
Do not eat any part of a deer that appears sick (unsteady on their feet)
Get your deer sampled for CWD testing and wait for the test results before consuming the deer
Wear rubber gloves when coming into contact with the deer
Minimize contact with brain, eyes, spinal cord, spleen, tonsils, or lymph nodes
Don't use household knives or utensils
Cutting and Processing
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Wear rubber or latex gloves
If processing deer from a CWD management zone, keep meat and trimmings from each deer
separate
Minimize handling of brain and spinal tissues
Do not cut through spinal column except when removing the head. Use a separate knife
designated for only this purpose
Remove all fat and connective tissue. This will also remove lymph nodes
Discard any meat that is bruised or discolored
Cleaning up
 Dispose of brain and spinal tissues in a landfill
 Thoroughly clean and sanitize work equipment and work areas with bleach after processing
 Wipe down counters with 50/50 solution of household chlorine bleach and water, and let them
air dry
CWD transmission to humans has not yet been reported, but it is
always better to be safe than sorry!!!