Bioluminescent mystery……..

Hello all 🙂 while doing my amino acid and protein assignment for biochemistry I came across a question that required me to explain the defence mechanism of Aquorea Victoria. This particular question was very interesting to me and so I wish to share my research with you.

Aquorea victoria also know as crystal jelly is a bioluminescent. This species has a very special defence mechanism which involves two proteins. The Green Fluorescent Protein (GFP) and aequorin protein. In the aequorin protein it causes the jellyfish to release flashes of bright blue light by releasing calcium, this is able to occur because of specific proteins that are found in the aequorin structure, it has three EF hand motifs that can act as binding sites. It is the Ca2+ that occupies the binding sites, when this happens the protein will undergo a change converting its prosthetic group coelenterazine through an oxidation reaction into the excited coelenteramide and CO2. This is now in its excited state and when it relaxes to the ground state, blue light is emitted.

After this blue light is emitted it is transduced into green light by the green florescent protein (GFP). GFP is made up of 238 amino acids, it is a very compact structure, within this structure there is a section called the chromophore, where the reactions take place to release the green light. At this chromophore centre there are three amino acids which are serine, tyrosine and glycine.  These three amino acids undergo an oxidation and cyclization reaction, resulting in the formation of double bonds which are the site and store that release energy from the electrons. The formation of these double bonds are very important as they absorb the blue light from the previously discussed protein aequorin and realse visible green light.

Hope you enjoyed reading 🙂 Ttyl

 

References :

  1. http://www.ebbep.com/docs/pglo/gfpstructure.pdf
  2. http://www.conncoll.edu/ccacad/zimmer/GFP-ww/Natural_Function.html
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