View source for 8ank


==Structure of the amyloid-forming peptide pEFIAWL from human GLP-1==
<StructureSection load='8ank' size='340' side='right'caption='[[8ank]], [[Resolution|resolution]] 1.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8ank]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8ANK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8ANK FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</scene></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=8ank FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8ank OCA], [https://pdbe.org/8ank PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8ank RCSB], [https://www.ebi.ac.uk/pdbsum/8ank PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8ank ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GLUC_HUMAN GLUC_HUMAN] Glucagon plays a key role in glucose metabolism and homeostasis. Regulates blood glucose by increasing gluconeogenesis and decreasing glycolysis. A counterregulatory hormone of insulin, raises plasma glucose levels in response to insulin-induced hypoglycemia. Plays an important role in initiating and maintaining hyperglycemic conditions in diabetes.<ref>PMID:8482423</ref> <ref>PMID:14557443</ref> <ref>PMID:14632334</ref>   GLP-1 is a potent stimulator of glucose-dependent insulin release. Play important roles on gastric motility and the suppression of plasma glucagon levels. May be involved in the suppression of satiety and stimulation of glucose disposal in peripheral tissues, independent of the actions of insulin. Have growth-promoting activities on intestinal epithelium. May also regulate the hypothalamic pituitary axis (HPA) via effects on LH, TSH, CRH, oxytocin, and vasopressin secretion. Increases islet mass through stimulation of islet neogenesis and pancreatic beta cell proliferation. Inhibits beta cell apoptosis.<ref>PMID:8482423</ref> <ref>PMID:14557443</ref> <ref>PMID:14632334</ref>   GLP-2 stimulates intestinal growth and up-regulates villus height in the small intestine, concomitant with increased crypt cell proliferation and decreased enterocyte apoptosis. The gastrointestinal tract, from the stomach to the colon is the principal target for GLP-2 action. Plays a key role in nutrient homeostasis, enhancing nutrient assimilation through enhanced gastrointestinal function, as well as increasing nutrient disposal. Stimulates intestinal glucose transport and decreases mucosal permeability.<ref>PMID:8482423</ref> <ref>PMID:14557443</ref> <ref>PMID:14632334</ref>   Oxyntomodulin significantly reduces food intake. Inhibits gastric emptying in humans. Suppression of gastric emptying may lead to increased gastric distension, which may contribute to satiety by causing a sensation of fullness.<ref>PMID:8482423</ref> <ref>PMID:14557443</ref> <ref>PMID:14632334</ref>   Glicentin may modulate gastric acid secretion and the gastro-pyloro-duodenal activity. May play an important role in intestinal mucosal growth in the early period of life.<ref>PMID:8482423</ref> <ref>PMID:14557443</ref> <ref>PMID:14632334</ref> 
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== Publication Abstract from PubMed ==
A large group of hormones are stored as amyloid fibrils in acidic secretion vesicles before they are released into the bloodstream and readopt their functional state. Here, we identify an evolutionarily conserved hexapeptide sequence as the major aggregation-prone region (APR) of gastrointestinal peptides of the glucagon family: xFxxWL. We determine nine polymorphic crystal structures of the APR segments of glucagon-like peptides 1 and 2, and exendin and its derivatives. We follow amyloid formation by CD, FTIR, ThT assays, and AFM. We propose that the pH-dependent changes of the protonation states of glutamate/aspartate residues of APRs initiate switching between the amyloid and the folded, monomeric forms of the hormones. We find that pH sensitivity diminishes in the absence of acidic gatekeepers and amyloid formation progresses over a broad pH range. Our results highlight the dual role of short aggregation core motifs in reversible amyloid formation and receptor binding.

Polymorphic amyloid nanostructures of hormone peptides involved in glucose homeostasis display reversible amyloid formation.,Horvath D, Durvanger Z, K Menyhard D, Sulyok-Eiler M, Bencs F, Gyulai G, Horvath P, Taricska N, Perczel A Nat Commun. 2023 Aug 1;14(1):4621. doi: 10.1038/s41467-023-40294-x. PMID:37528104<ref>PMID:37528104</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8ank" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Durvanger Z]]