Murder at the airport
The case
You have been called to assist in a crime scene investigation: the body of an American tourist was found at the airport. He seems to have suffered from convulsions and internal bleeding. Detectives at the crime scene found a
drink carton with some sort of beverage: it still contained some fluid which looks like milk.
This may be key evidence.
The fluid was sent to the lab and you receive a list of the components of the beverage. Some small molecules such as sugar were found, but also four unidentified proteins were detected. It is your job to analyse these proteins to see if you can help figuring out how the tourist died.
Use your computer to search for and study information about these proteins.
Some of the powerful tools and databases used in bioinformatics will
help you during your investigation.
Identification of the suspicious proteins
A list containing the amino acid sequences of the 4 proteins (called suspect1 through 4) is given
here.
Attention: The amino acid sequences are given in the 1-letter code most scientists use. This was discussed in the introduction. If you do not know the code, you can use
this list.
You now have enough information to start your investigation. For each of the unidentified proteins you must answer these five questions:
- Which protein is it?
- From which organism does it originate?
- What is the function of this protein?
- Is this protein "guilty"? Could it be responsible for the death of the tourist? Why (not)?
- Does the protein have any other remarkable features?
You can use this form (Word | PDF) to
write down you answers.
BLAST is a program used to compare a given protein sequence with all the protein sequences present in the
SwissProt
database. This database contains all protein sequences known to science.
We will use BLAST within
MRS (a tool to
search many different databases commonly used in bioinformatics).
To help you get acquainted with MRS and BLAST, we will take protein suspect1 and guide you through the process.
Afterwards, you can continue your investigation with suspect2, 3, and 4
to find out which of the suspects is guilty.
The next page gives you instructions on how to work through the questions about suspect1 and how to
interpret your results.
