5t7r: Difference between revisions
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==A6-A11 trans-dicarba human insulin== | ==A6-A11 trans-dicarba human insulin== | ||
<StructureSection load='5t7r' size='340' side='right' caption='[[5t7r]], [[Resolution|resolution]] 1.55Å' scene=''> | <StructureSection load='5t7r' size='340' side='right'caption='[[5t7r]], [[Resolution|resolution]] 1.55Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[5t7r]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5T7R OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5T7R FirstGlance]. <br> | <table><tr><td colspan='2'>[[5t7r]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5T7R OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5T7R FirstGlance]. <br> | ||
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== Function == | == Function == | ||
[[http://www.uniprot.org/uniprot/INS_HUMAN INS_HUMAN]] Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. | [[http://www.uniprot.org/uniprot/INS_HUMAN INS_HUMAN]] Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. | ||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The structural transitions required for insulin to activate its receptor and initiate regulation of glucose homeostasis are only partly understood. Here, using ring-closing metathesis, we substitute the A6-A11 disulfide bond of insulin with a rigid, non-reducible dicarba linkage, yielding two distinct stereo-isomers (cis and trans). Remarkably, only the cis isomer displays full insulin potency, rapidly lowering blood glucose in mice (even under insulin-resistant conditions). It also posseses reduced mitogenic activity in vitro. Further biophysical, crystallographic and molecular-dynamics analyses reveal that the A6-A11 bond configuration directly affects the conformational flexibility of insulin A-chain N-terminal helix, dictating insulin's ability to engage its receptor. We reveal that in native insulin, contraction of the Calpha-Calpha distance of the flexible A6-A11 cystine allows the A-chain N-terminal helix to unwind to a conformation that allows receptor engagement. This motion is also permitted in the cis isomer, with its shorter Calpha-Calpha distance, but prevented in the extended trans analogue. These findings thus illuminate for the first time the allosteric role of the A6-A11 bond in mediating the transition of the hormone to an active conformation, significantly advancing our understanding of insulin action and opening up new avenues for the design of improved therapeutic analogues. | |||
Insulin in motion: The A6-A11 disulfide bond allosterically modulates structural transitions required for insulin activity.,van Lierop B, Ong SC, Belgi A, Delaine C, Andrikopoulos S, Haworth NL, Menting JG, Lawrence MC, Robinson AJ, Forbes BE Sci Rep. 2017 Dec 8;7(1):17239. doi: 10.1038/s41598-017-16876-3. PMID:29222417<ref>PMID:29222417</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 5t7r" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Molecular Playground/Insulin|Molecular Playground/Insulin]] | |||
== References == | == References == | ||
<references/> | <references/> | ||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Large Structures]] | |||
[[Category: Forbes, B E]] | [[Category: Forbes, B E]] | ||
[[Category: Lawrence, M C]] | [[Category: Lawrence, M C]] |
Revision as of 09:22, 19 June 2019
A6-A11 trans-dicarba human insulinA6-A11 trans-dicarba human insulin
Structural highlights
Disease[INS_HUMAN] Defects in INS are the cause of familial hyperproinsulinemia (FHPRI) [MIM:176730].[1] [2] [3] [4] Defects in INS are a cause of diabetes mellitus insulin-dependent type 2 (IDDM2) [MIM:125852]. IDDM2 is a multifactorial disorder of glucose homeostasis that is characterized by susceptibility to ketoacidosis in the absence of insulin therapy. Clinical fetaures are polydipsia, polyphagia and polyuria which result from hyperglycemia-induced osmotic diuresis and secondary thirst. These derangements result in long-term complications that affect the eyes, kidneys, nerves, and blood vessels.[5] Defects in INS are a cause of diabetes mellitus permanent neonatal (PNDM) [MIM:606176]. PNDM is a rare form of diabetes distinct from childhood-onset autoimmune diabetes mellitus type 1. It is characterized by insulin-requiring hyperglycemia that is diagnosed within the first months of life. Permanent neonatal diabetes requires lifelong therapy.[6] [7] Defects in INS are a cause of maturity-onset diabetes of the young type 10 (MODY10) [MIM:613370]. MODY10 is a form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.[8] [9] [10] Function[INS_HUMAN] Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. Publication Abstract from PubMedThe structural transitions required for insulin to activate its receptor and initiate regulation of glucose homeostasis are only partly understood. Here, using ring-closing metathesis, we substitute the A6-A11 disulfide bond of insulin with a rigid, non-reducible dicarba linkage, yielding two distinct stereo-isomers (cis and trans). Remarkably, only the cis isomer displays full insulin potency, rapidly lowering blood glucose in mice (even under insulin-resistant conditions). It also posseses reduced mitogenic activity in vitro. Further biophysical, crystallographic and molecular-dynamics analyses reveal that the A6-A11 bond configuration directly affects the conformational flexibility of insulin A-chain N-terminal helix, dictating insulin's ability to engage its receptor. We reveal that in native insulin, contraction of the Calpha-Calpha distance of the flexible A6-A11 cystine allows the A-chain N-terminal helix to unwind to a conformation that allows receptor engagement. This motion is also permitted in the cis isomer, with its shorter Calpha-Calpha distance, but prevented in the extended trans analogue. These findings thus illuminate for the first time the allosteric role of the A6-A11 bond in mediating the transition of the hormone to an active conformation, significantly advancing our understanding of insulin action and opening up new avenues for the design of improved therapeutic analogues. Insulin in motion: The A6-A11 disulfide bond allosterically modulates structural transitions required for insulin activity.,van Lierop B, Ong SC, Belgi A, Delaine C, Andrikopoulos S, Haworth NL, Menting JG, Lawrence MC, Robinson AJ, Forbes BE Sci Rep. 2017 Dec 8;7(1):17239. doi: 10.1038/s41598-017-16876-3. PMID:29222417[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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