Peptide: Difference between revisions
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<applet load=" | <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. | 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== | ==Peptides & Backbones== | ||
This is the <scene name='Peptide/Emartz_view1/ | 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). | ||
==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. | |||
Latest revision as of 12:01, 31 January 2020
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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 peptides, with examples.
Peptides & BackbonesPeptides & Backbones
This is the of 1 amino acid. Adding to the backbone with an additional amino acid on each side gives a (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 (tri-alanine). Adding a carbon chain plus an NH3 on the first amino acid gives . Adding to the 3rd amino acid gives isoleucine: Lys-Ala-Ile. The 4th amino acid is threonine with its hydroxyl, giving . Here is the shape of the (4 AAs). The stick representation has too much detail for larger proteins, so the α-carbons are connected with a line called the . Showing only the makes it easier to see the path of the protein chain (its secondary and tertiary structure).
See AlsoSee Also
External ResourcesExternal Resources
Content AttributionContent Attribution
The above scenes in Jmol were adapted from the chapter Peptides and Backbones in a tutorial on Hemoglobin first written by Eric Martz as a RasMol Movie Script released in March, 1996, which was released as a Hemoglobin Tutorial implemented with Chime in September, 1997, and a Hemoglobin Tutorial implemented with Jmol in July 2007.