Reflection on Proteins
Well well, proteins not new but still good topic, twas educational especially the vids. So proteins play a very important roles in our bodies, such as Structural, Transportation, Receptors, Storage, Hormones , Antibodies and enzymes.
So the first primary structure is just the linear sequence of aa bonded together by peptide bonds.
Secondary is primaly peptide and hydrogen bonding there are two form alpha helix and beta pleated sheet
the alpha helix is not so unknown to us, u see it everyday and wash it frequently…I hope…lol
HAIR and our Nails!
Both of these are both made of the protein Keratin which is a alpha helix. In the alpha the amino acids link together to form the coil and there are approximately 3.6 amino acids per turn of the helix (coil), bonding occurs between the oxygen of the carbonyl group and the hydrogen of amino group on the 4th aa. These are fibrous protein playing structural roles. Keratin is also a fibrous protein.
Hair tip: Our hair doesn’t only have hydrogen bonding but also disulphide, sugar and salt bridges. Healthy hair tips girls and boys, we must keep a clean and healthy scalp and also eat and exercise properly to even our follicles good. A word to the wise as much as I love that girls hair over processing and dying hair can lead to early hair loss and thinning so kids lets try and do these things not so much. 😀
The beta pleated sheet can be found in our clothing. SILK!
Tertiary structure, now this is where things get interesting this is the 3D structure given to the polypeptide chain, which is held together by hydrogen bonds, electrostatic bonds, if present disulphide and hydrophobic interactions. Enzyme possess tertiary structure which is very important to them in term of catalytic activity. They are also globular.
Quaternary structure possess all the bonding present in tertiary structure but has more than one polypeptide chain present as seen in haemoglobin that functions in a transport form as it carries oxygen to the body’s cells.
Proteins can be denatured but it occurs differently in each level. Denaturation is the disruption of the bonding in the tertiary and secondary structures. Denatutration can occur through extreme heat and pH. Afinesen experiment he tested it on Ribonuclease A and showed that when present in urea and 2mercaploethanol to break the disulphide bridges present. He found that unfolding of the protein only occurred when in these substances and that it re-folded when not in it. Dialysis removed the solution from the protein, this show that once the primary structure is kept intact a protein can always refold.
That was a long, but now I’ll remember some stuff!
Wikipedia. org. “Protein Structure”. http://en.wikipedia.org/wiki/Protein_structure
Informaticsindianna. “Afinsen eperiment” http://www.informatics.indiana.edu/predrag/classes/2008springi619/anfinsen.pdf
About.com “Protein Function”http://biology.about.com/od/molecularbiology/a/aa101904a.htm
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