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Protein subunits/protein structure help

Posted: Mon Dec 16, 2013 12:21 pm
by Espike
I'm doing the Tree of Life advanced project and while on Genbank I was searching hemoglobin in different species, and I found there were listing like Hemoglobin subunit alpha, or hemoglobin subunit epsilon, etc. Are these subunits significant? Also how do I find the protein sequences on Genbank in order to compare them? Any help is appreciated. Thanks in advance

Re: Protein subunits/protein structure help

Posted: Tue Dec 17, 2013 12:46 pm
by deleted-71536
Hi Espike,

This is a really fascinating project (https://www.sciencebuddies.org/science- ... p001.shtml), which looks at how protein structures relate to the relationships among different organisms.

Hemoglobin is a very interesting molecule, considering that it is our oxygen carrying protein. The subunits are very important. In fact, different subunits are what give fetal hemoglobin a higher affinity for oxygen than adult hemoglobin. Read here for more information about subunits: http://en.wikipedia.org/wiki/Hemoglobin I also suggest that you do a bit of research on your own.

If the globin subunits are different enough, they may have different designations for different animals. The human hemoglobin subunits are usually alpha, beta, and gamma, but there are other subunits like epsilon in different animals. Again, you may have to do a bit more research to get further information on this.

To find the protein sequences on Genbank, go to the main page (http://www.ncbi.nlm.nih.gov/genbank/), then use the drop-down menu to select Protein. Type the name of the protein and the species name (e.g., hemoglobin Homo sapiens) in the search bar, then press enter. You will scroll through the results and pick one that you want to view. When you compare different animals, the best thing is to compare the same subunit of hemoglobin. I believe the alpha subunit is fairly common among different animals, so that might be a good one to use.

Once you click on the search result you want to view, click FASTA to view the amino acid sequence. This is the sequence you would copy and paste into BLAST.

I hope that helps you get going. Please post again (in this same thread) if you have more questions.

Heather