BerkiGEM2007Present1

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Hannah Cole- Alternatives To Hemoglobin:

Over the summer I investigated and created two alternatives to the hemoglobin part in our device. I worked with two genes we believed might allow our blood to carry more oxygen than hemoglobin.

The first gene I will discuss is H-NOX (Heme-Nitric oxide and Oxygen bonding). H-NOX is a heme-based sensor that is found in bacteria. H-NOX is able to bond to Oxygen using a distal pocket tyrosine. For this gene I added the T7 promoter we created for this project, an RBS site, and lastly a Bca1092 terminator. As I said previously this part would replace the hemoglobin part in our final device. When I assayed this part the results were inconclusive. The part was assembled correctly but the assay didn't show strong signs of expression.

The second gene I explored was Sperm Whale Myoglobin. Myoglobin is a monomeric protein that behaves as an intracellular oxygen storage site. Sperm whale myoglobin in particular is easily found in large amounts in the whale's muscle tissue. The construction of this part was very similar to that of the H-NOX composite part. Used the same promoter, terminator, and RBS. The assay for Myoglobin showed a bit more promise but couldn't conclusively show that Myoglobin was binding to oxygen.


Heme

Heme is a prosthetic group to hemoglobin. Generally, heme consists of an iron atom surrounded by a porphyrin ring. Each hemoglobin molecule is capable of binding up to four heme groups. One of the most important functions of heme is to assist in the transportation of diatomic gases. When it comes to red blood cells, heme and hemoglobin are the components that allow the binding of oxygen, which the red blood cells can then deliver to the entire body.

The biosynthetic pathway for heme demonstrates that there are numerous enzymes, or heme genes, involved in the production of heme. For our purposes, we worked solely with hemA, hemB, hemC, and hemD because over-accumulation of heme in our cells would result in toxicity.