View source for 1lkq


==NMR STRUCTURE OF HUMAN INSULIN MUTANT ILE-A2-GLY, VAL-A3-GLY, HIS-B10-ASP, PRO-B28-LYS, LYS-B29-PRO, 20 STRUCTURES==
<StructureSection load='1lkq' size='340' side='right'caption='[[1lkq]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1lkq]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LKQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LKQ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 20 models</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1lkq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1lkq OCA], [https://pdbe.org/1lkq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1lkq RCSB], [https://www.ebi.ac.uk/pdbsum/1lkq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1lkq ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/INS_HUMAN INS_HUMAN] Defects in INS are the cause of familial hyperproinsulinemia (FHPRI) [MIM:[https://omim.org/entry/176730 176730].<ref>PMID:3470784</ref> <ref>PMID:2196279</ref> <ref>PMID:4019786</ref> <ref>PMID:1601997</ref>   Defects in INS are a cause of diabetes mellitus insulin-dependent type 2 (IDDM2) [MIM:[https://omim.org/entry/125852 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.<ref>PMID:18192540</ref>   Defects in INS are a cause of diabetes mellitus permanent neonatal (PNDM) [MIM:[https://omim.org/entry/606176 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.<ref>PMID:17855560</ref> <ref>PMID:18162506</ref>   Defects in INS are a cause of maturity-onset diabetes of the young type 10 (MODY10) [MIM:[https://omim.org/entry/613370 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.<ref>PMID:18192540</ref> <ref>PMID:18162506</ref> <ref>PMID:20226046</ref> 
== Function ==
[https://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.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/lk/1lkq_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1lkq ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The A and B chains of insulin combine to form native disulfide bridges without detectable isomers. The fidelity of chain combination thus recapitulates the folding of proinsulin, a precursor protein in which the two chains are tethered by a disordered connecting peptide. We have recently shown that chain combination is blocked by seemingly conservative substitutions in the C-terminal alpha-helix of the A chain. Such analogs, once formed, nevertheless retain high biological activity. By contrast, we demonstrate here that chain combination is robust to non-conservative substitutions in the N-terminal alpha-helix. Introduction of multiple glycine substitutions into the N-terminal segment of the A chain (residues A1-A5) yields analogs that are less stable than native insulin and essentially without biological activity. (1)H NMR studies of a representative analog lacking invariant side chains Ile(A2) and Val(A3) (A chain sequence GGGEQCCTSICSLYQLENYCN; substitutions are italicized and cysteines are underlined) demonstrate local unfolding of the A1-A5 segment in an otherwise native-like structure. That this and related partial folds retain efficient disulfide pairing suggests that the native N-terminal alpha-helix does not participate in the transition state of the reaction. Implications for the hierarchical folding mechanisms of proinsulin and insulin-like growth factors are discussed.

Mechanism of insulin chain combination. Asymmetric roles of A-chain alpha-helices in disulfide pairing.,Hua QX, Chu YC, Jia W, Phillips NF, Wang RY, Katsoyannis PG, Weiss MA J Biol Chem. 2002 Nov 8;277(45):43443-53. Epub 2002 Aug 23. PMID:12196530<ref>PMID:12196530</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1lkq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Insulin 3D Structures|Insulin 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Chu YC]]
[[Category: Hua QX]]
[[Category: Jia W]]
[[Category: Katsoyannis PG]]
[[Category: Philips NF]]
[[Category: Wang RY]]
[[Category: Weiss MA]]