Protein: Difference between revisions
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=== Primary Structure === | === Primary Structure === | ||
The [[Primary structure|primary structure]] is the sequence of [[Amino acids|amino acids]]. There are 20 different amino acids found in nature. This is determined by the [[DNA|DNA]] sequence that encodes for that particular protein, called the [[Gene|gene]]. <br> | The [[Primary structure|primary structure]] is the sequence of [[Amino acids|amino acids]] joined togther by peptide bond. There are 20 different amino acids found in nature. This is determined by the [[DNA|DNA]] sequence that encodes for that particular protein, called the [[Gene|gene]]. <br> | ||
=== Secondary Structure<br> === | === Secondary Structure<br> === | ||
Revision as of 23:18, 11 November 2011
A protein is a biological molecule which is made up of amino acids. The amino acids join together with peptide bond to form a polypeptide chain. A protein can be made up of a single polypeptide chain or multiple polypeptides linked together. Examples of proteins include enzymes, receptors and hormones. They are found in every form of life from viruses to bacteria, yeasts to humans.One important technique used to analyse proteins in SDS polyacrylamide-gel electrophoresis (SDS-PAGE)
Structure
A protein has several 'layers' of structure [1].
Primary Structure
The primary structure is the sequence of amino acids joined togther by peptide bond. There are 20 different amino acids found in nature. This is determined by the DNA sequence that encodes for that particular protein, called the gene.
Secondary Structure
Secondary structure is the first level of protein folding. The two main folding structures of a protein are alpha-helix or beta-sheet depending on the sequence of amino acids. This, in turn, allows the protein to have a hydrophobic core and a hydrophilic surface.
Tertiary Structure
Tertiary structure relates to the protein function. If the tertiary structure is wrong then the protein is unlikely to function properly. Tertiary structure is held together by either hydrogen bonds or disulphide bridges depending on the amio acids present. Finally, if there is more than one peptide chains linked together to form a protein then you get a quarternary structure.
Quarternary Structure
One or more tertiary stucture of protein build up a quarternary structure.
See also
References
- ↑ Elliott.W.H, Elliott.D.C (1997) Biochemistry and Molecular Biology. New York, United States:Oxford University Press.pp.47-49.ISBN 0199271992