Peptide: Difference between revisions

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Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

Eran Hodis, Joel L. Sussman, Eric Martz, Wayne Decatur

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-<applet load="pepb27_4.pdb" size="300" color="white" frame="true" caption="Peptides are small chains of amino acids." align="right" />
+<applet load="" scene="Peptide/Emartz_view1/8" size="500" color="white" frame="true" caption="Peptides, small chains of amino acids." align="right" />
-Peptides are chains of amino acids linked by peptide bonds. Long peptides, or polypeptides, are called proteins.
+Peptides are short chains of amino acids linked by peptide bonds. By convention, a '''peptide''' is not more than 30-50 amino acids in length.  Longer chains of amino acids are called polypeptides or proteins. Wikipedia offers a good discussion of [http://en.wikipedia.org/wiki/Peptide peptides, with examples].
 ==Peptides & Backbones==
-This is the <scene name='Peptide~Emartz_view1~2'>backbone</scene> of 1 amino acid.  Adding to the backbone with an additional amino acid on each side gives a <scene name='Peptide~Emartz_view2~1'>tripeptide</scene> (3 amino acids).  No side groups are shown, and most hydrogens are omitted.  Now each amino acid has a 1 carbon side group so we have <scene name='Peptide~Emartz_view3~1'>Ala-Ala-Ala</scene> (tri-alanine).  Adding a carbon chain plus an NH3 on the first amino acid gives <scene name='Peptide~Emartz_view4~1'>Lys-Ala-Ala</scene>.
+This is the <scene name='Peptide/Emartz_view1/8'>backbone</scene> of 1 amino acid.  Adding to the backbone with an additional amino acid on each side gives a <scene name='Peptide/Emartz_view2/8'>tripeptide</scene> (3 amino acids).  No side groups are shown, and most hydrogens are omitted.  Now each amino acid has a 1 carbon side group so we have <scene name='Peptide/Emartz_view3/6'>Ala-Ala-Ala</scene> (tri-alanine).  Adding a carbon chain plus an NH3 on the first amino acid gives <scene name='Peptide/Emartz_view4/7'>Lys-Ala-Ala</scene>.  Adding <scene name='Peptide/Emartz_view5/6'> three more carbons</scene> to the 3rd amino acid gives isoleucine: Lys-Ala-Ile.  The 4th amino acid is threonine with its hydroxyl, giving <scene name='Peptide/Emartz_view6/4'>Lys-Ala-Ile-Thr</scene>.  Here is the shape of the <scene name='Peptide/Emartz_view7/2'>tetrapeptide</scene> (4 AAs).  The stick representation has too much detail for larger proteins, so the α-carbons are connected with a line called the <scene name='Peptide/Emartz_view8/4'>backbone trace</scene>.  Showing only the <scene name='Peptide/Emartz_view9/6'>backbone</scene> makes it easier to see the path of the protein chain (its secondary and tertiary structure).
-<scene name='Peptide~Emartz_view5~1'>Adding three more carbons</scene> to the 3rd amino acid gives [[isoleucine]]: Lys-Ala-Ile.  The 4th amino acid is threonine with its hydroxyl, giving Lys-Ala-Ile-Thr.  Here is the shape of the tetrapeptide (4 AAs).  The stick representation has too much detail for larger proteins, so the α-carbons are connected with a line called the backbone trace.  Showing only the backbone makes it easier to see the path of the protein chain (its secondary and tertiary structure).
+==See Also==
+*[[Thermal motion of peptide]]
+*[[Basics of Protein Structure]]
+==External Resources==
+*[http://pepx.switchlab.org/ PepX: a structural database of protein-peptide complexes]
+==Content Attribution==
+The above scenes in Jmol were adapted from the chapter ''Peptides and Backbones'' in a tutorial on Hemoglobin first written by [[User:Eric Martz|Eric Martz]] as a ''RasMol Movie Script'' released in March, 1996, which was released as a [http://molviz.org/hemoglob Hemoglobin Tutorial] implemented with [[Chime]] in September, 1997, and a [http://molviz.org/hemoglobin Hemoglobin Tutorial] implemented with [[Jmol]] in July 2007.