Murder at the airport - Answers

Below you will find the answers to the five questions about each one of the suspicious proteins.

The five questions

  1. Which protein is it?
  2. From which organism is it?
  3. What is the function of this protein?
  4. Is this protein guilty? Could it be responsible for the death of the tourist? Why (not)?
  5. Does the protein have any other remarkable features?

Suspect1

  1. Casa1_bovin. This sequence represents amino acids 16-214 of alpha-1-casein of the cow (amino acids 1-15 are a signal peptide. This is the main component of milk. Keywords: Milk, Comments: Secreted in milk.
  2. Bos Taurus (bovine/cow)
  3. Comments: Important role in the capacity of milk to transport calcium phosphate.
  4. The protein is not suspicious, it comes naturally in milk.
  5. No important features for our investigation.

Suspect2

  1. Amys_human, the human alpha-amylase from saliva.
  2. Human
  3. Endohydrolysis of 1,4-alpha-D-glucosidiclinkages in oligosaccharides and polysaccharides.
  4. The enzyme comes from the victim and is not responsible for his death.
  5. The given sequence starts at number 16 of the database sequence (QYSSN). MKLFWLLFTI GFCWA(1-15) is the signal peptide of this protein.

Suspect3

  1. Hrtd_croat. Hemorrhagic metalloproteinase (EC 3.4.24.42) (Atrolysin D/C). Hemorrhagic means that it causes bleedings.
  2. Crotalus atrox (Western diamondback rattlesnake).
  3. It is a hydrolase, a metalloproteinase with a zinc cofactor. It is the toxin of a very venomous rattlesnake.
  4. The enzyme is very suspicious because it causes internal bleedings. In Synonyms, you can see the word "toxin", in Comments you see "snake venom".
  5. Zinc protease. The sequence in the database is much longer, but this shows the functional part of the protein, amino acids 191-393.

Suspect4

  1. Lacb_bovin. This is the precursor beta-lactoglobulin of the cow, amino acids 17-178 (1-16 is signal peptide). This is the main milk protein.
  2. Bos Taurus (bovine/cow)
  3. Under Function in the Comments: Primary component of whey, it binds retinol and is probably involved in the transport of that molecule. Keywords: Allergen; Milk; Retinol-binding; Signal; Transport
  4. The enzyme is not suspicious. In keywords: Milk. In Comments: Tissue specificity: Synthesized in mammary gland and secreted in milk.
  5. From the comments: Causes an allergic reaction in human. Is one of the causes of cow's milk allergy.

Final conclusion

The victim died of drinking milk containing a snake venom.