Protein structure: Difference between revisions
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[[Proteins|Proteins]] are made up of polymers of [[Amino acids|amino acids]]. The amino acids are joined together by [[Peptide bonds|peptide bonds]] in a [ | [[Proteins|Proteins]] are made up of polymers of [[Amino acids|amino acids]]. The amino acids are joined together by [[Peptide bonds|peptide bonds]] in a [[Condensation reaction|condensation reaction]]. This series of peptide bonds is also known as the [[Polypeptide|polypeptide]] backbone, off which are side chains made up of amino acids. This type of reaction is catalysed by the [[Ribosome|ribosome]] in the [[Cytoplasm|cytoplasm]] and releases a [[Water|water]] molecule. There are four levels of protein structure. The [[Primary structure|primary structure]] is the linear sequence of [[Amino acids|amino acids]] in a polypeptide chain <ref>http://www.chemguide.co.uk/organicprops/aminoacids/proteinstruct.html</ref>. The main [[Secondary structure|secondary structures]] of proteins are the [[Alpha-helix|alpha helix]] and the [[beta pleated sheet|beta pleated sheet]]. The protein then continues to fold forming a three-dimensional structure. This is known as the [[Tertiary structure|tertiary structure]]. If two or more tertiary structures form a single structure then it is a [[Quaternary structure|quaternary structure]]. An example of a quaternary structure are [[Haemoglobin|haemoglobin]] molecules, that are made up of four [[Globin|globin]] [[Molecules|molecules]]. These are also known as [[Red blood cells|red blood cells]] and are found in [[Blood|blood]] <ref>Alberts et al., (2008) Molecular Biology of the Cell, 5th Edition, Garland Science, Chapter 3, Page 136</ref>. | ||
=== References === | === References === | ||
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Revision as of 06:36, 17 October 2012
Proteins are made up of polymers of amino acids. The amino acids are joined together by peptide bonds in a condensation reaction. This series of peptide bonds is also known as the polypeptide backbone, off which are side chains made up of amino acids. This type of reaction is catalysed by the ribosome in the cytoplasm and releases a water molecule. There are four levels of protein structure. The primary structure is the linear sequence of amino acids in a polypeptide chain [1]. The main secondary structures of proteins are the alpha helix and the beta pleated sheet. The protein then continues to fold forming a three-dimensional structure. This is known as the tertiary structure. If two or more tertiary structures form a single structure then it is a quaternary structure. An example of a quaternary structure are haemoglobin molecules, that are made up of four globin molecules. These are also known as red blood cells and are found in blood [2].
References
- ↑ http://www.chemguide.co.uk/organicprops/aminoacids/proteinstruct.html
- ↑ Alberts et al., (2008) Molecular Biology of the Cell, 5th Edition, Garland Science, Chapter 3, Page 136