Insulin Structure & Function: Difference between revisions
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==Structure== | ==Structure== | ||
Insulin is composed of two different types of peptide chains. <scene name='34/347648/Chain_a/1'>Chain A</scene> has 21 amino acids and <scene name='34/347648/Chain_b/1'>Chain B</scene> has 30 amino acids. Both chains contain <scene name='34/347648/Secondary_structures/1'>alpha helices</scene> but no beta strands. There are 3 conserved <scene name='34/347648/Disulfide_bonds/1'>disulfide bridges</scene> which help keep the two chains together. Insulin can also form <scene name='User:Whitney_Stoppel/sandbox1/Insulin_dimer/2'>dimers</scene> in solution due to the hydrogen bonding between the B chains (shown as white lines). The dimers can further interact to form <scene name='User:Whitney_Stoppel/sandbox1/Insulin_hexamer/4'>hexamers</scene> due to interaction between hydrophobic surfaces. This <scene name='User:Whitney_Stoppel/sandbox1/Insulin_ph7/2'>scene highlights</scene> the hydrophobic (gray) and polar (purple) parts of an insulin monomer at a pH of 7. | Insulin is composed of two different types of peptide chains. <scene name='34/347648/Chain_a/1'>Chain A</scene> has 21 amino acids and <scene name='34/347648/Chain_b/1'>Chain B</scene> has 30 amino acids. Both chains contain <scene name='34/347648/Secondary_structures/1'>alpha helices</scene> but no beta strands. There are 3 conserved <scene name='34/347648/Disulfide_bonds/1'>disulfide bridges</scene> which help keep the two chains together. Insulin can also form <scene name='User:Whitney_Stoppel/sandbox1/Insulin_dimer/2'>dimers</scene> in solution due to the hydrogen bonding between the B chains (shown as white lines). The dimers can further interact to form <scene name='User:Whitney_Stoppel/sandbox1/Insulin_hexamer/4'>hexamers</scene> due to interaction between hydrophobic surfaces. This <scene name='User:Whitney_Stoppel/sandbox1/Insulin_ph7/2'>scene highlights</scene> the hydrophobic (gray) and polar (purple) parts of an insulin monomer at a pH of 7. | ||
A number of insulin variants have been made to favor either the monomeric or hexameric form. Deletion of the <scene name='34/347648/Hexamer_bchaincterminus/2'>five C terminal residues of the B chain</scene> creates a monomer only form. This portion of the B chain is involved in <scene name='34/347648/Dimer_bchainctermhbond/1'>hydrogen bonds</scene> between the B chain of one monomer and the A (marked C) and B (marked D) chain of another monomer. | |||
</StructureSection> | </StructureSection> | ||
==3D structures of insulin== | ==3D structures of insulin== | ||