Peptide: Difference between revisions

==Peptides & Backbones==

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).

==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.