Protein: Difference between revisions
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A protein is a biological molecule which is made up of [[Amino acid|amino acids]]. The [[Amino acids|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|polypeptides]] linked together. Examples of proteins include [[Enzyme|enzymes]], [[Receptor|receptors]] and [[Hormone|hormones.]] They are found in every form of life from viruses to bacteria, yeasts to humans. | A protein is a biological molecule which is made up of [[Amino acid|amino acids]]. The [[Amino acids|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|polypeptides]] linked together. Examples of proteins include [[Enzyme|enzymes]], [[Receptor|receptors]] and [[Hormone|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<br> == | == Structure<br> == | ||
A protein has several 'layers' of structure. | A protein has several 'layers' of structure. | ||
=== Primary Structure === | === Primary Structure === | ||
The [[Primary structure|primary structure]] is the sequence of [[Amino acids|amino acids]]. 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]]. 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> === | ||
[[Secondary structure|Secondary structure]] is the first level of protein folding. A protein can fold in two different ways or not at all. It can either fold as an [[Alpha-helix|alpha-helix or]] a [[Beta-sheet|beta-sheet]] depending on the sequence of [[Amino acids|amino acids]]. <br> | [[Secondary structure|Secondary structure]] is the first level of protein folding. A protein can fold in two different ways or not at all. It can either fold as an [[Alpha-helix|alpha-helix or]] a [[Beta-sheet|beta-sheet]] depending on the sequence of [[Amino acids|amino acids]]. <br> | ||
=== Tertiary Structure<br> === | === Tertiary Structure<br> === | ||
[[Tertiary structure|Tertiary structure]] relates to the protein function. If the [[Tertiary structure|tertiary structure]] is wrong then the protein is unlikely to function properly. [[Tertiary structure|Tertiary structure]] is held together by either [[Hydrogen bonds|hydrogen bonds]] or [[Disulphide bridges|disulphide bridges]] depending o the [[Amino acids|amio acids]] present. Finally, if there are more than one peptide chains linked together to form a protein then you get a [[Quarternary structure|quarternary structure]].<br> | [[Tertiary structure|Tertiary structure]] relates to the protein function. If the [[Tertiary structure|tertiary structure]] is wrong then the protein is unlikely to function properly. [[Tertiary structure|Tertiary structure]] is held together by either [[Hydrogen bonds|hydrogen bonds]] or [[Disulphide bridges|disulphide bridges]] depending o the [[Amino acids|amio acids]] present. Finally, if there are more than one peptide chains linked together to form a protein then you get a [[Quarternary structure|quarternary structure]].<br> | ||
=== Quarternary Structure<br> === | === Quarternary Structure<br> === | ||
One or more tertiary stucture of protein build up a quarternary structure.<br> | One or more tertiary stucture of protein build up a quarternary structure.<br> | ||
== See also<br> == | == See also<br> == | ||
*[http://bms.ncl.ac.uk/wiki/index.php/Amino_acids Amino acid]<br> | *[http://bms.ncl.ac.uk/wiki/index.php/Amino_acids Amino acid]<br> | ||
== References<br> == | == References<br> == | ||
<br> | <br> | ||
Revision as of 17:30, 20 November 2010
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.
Primary Structure
The primary structure is the sequence of amino acids. 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. A protein can fold in two different ways or not at all. It can either fold as an alpha-helix or a beta-sheet depending on the sequence of amino acids.
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 o the amio acids present. Finally, if there are 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