Basics of Protein Structure: Difference between revisions

← Older edit Newer edit →

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

Joel L. Sussman, Ann Taylor, Eric Martz

@@ Line 22: / Line 22: @@
 The third level of structure, or tertiary structure, is how the secondary structures pack together to form the overall form of the entire peptide chain. Side chains play an important role in tertiary structure formation, especially the burying of hydrophobic ("water fearing") amino acids in the middle of the structure. In <scene name='60/604417/Hydrophilic/1'>this view</scene>, {{Template:ColorKey_Hydrophobic}} residues are grey and {{Template:ColorKey_Polar}} are shown in light purple. Water molecules are shown with red balls; notice that they tend to be close to the hydrophilic (water loving) groups. Some proteins, like insulin, are also stabilized by<scene name='60/604417/Disulfide_bonds/1'> covalent bonds between the sulfur atoms</scene> (shown in yellow) called disulfide bonds.
-Not all proteins have the fourth level of structure, quaternary structure. Quaternary structure is the association of more than one chain to form a larger structure. Insulin forms a <scene name='82/821037/T6/1'>hexamer</scene>. Quaternary structure can be very important in how the protein functions. Minor changes in insulin's sequence leads to tighter or weaker association between the chains, and is the difference between long lasting and quick acting insulin.
+Not all proteins have the fourth level of structure, quaternary structure. Quaternary structure is the association of more than one chain to form a larger structure. Insulin forms a <scene name='60/604417/Hexamer/2'>hexamer</scene>. Quaternary structure can be very important in how the protein functions. Minor changes in insulin's sequence leads to tighter or weaker association between the chains, and is the difference between long lasting and quick acting insulin. For a more in depth discussion about insulin's structure and function, please visit the [[Insulin]] page.
-== Ways of representing protein structure ==
-Protein structures can be displayed in many different ways.  In <scene name='57/575866/Spacefill_segment/1'>spacefilling</scene> models, all of the non-hydrogen atoms are shown as spheres with their van der Waals radii.  In the <scene name='57/575866/Ball_and_stick_segment/1'>ball and stick</scene> model, the atoms are shown as smaller balls, connected by sticks; this is further simplified in the <scene name='57/575866/Stick_segment/1'>stick</scene> model, which only shows the bonds between atoms.  <scene name='57/575866/Backbone/2'>Backbone</scene> shows only the N-Calpha-C=O repeating unit; the <scene name='57/575866/Cartoon/4'>cartoon</scene> representation shows the secondary structures.