scholarly journals Structure-function relationships of brazzein variants with altered interactions with the human sweet taste receptor

2016 ◽  
Vol 25 (3) ◽  
pp. 711-719 ◽  
Author(s):  
Kiran K. Singarapu ◽  
Marco Tonelli ◽  
John L. Markley ◽  
Fariba M. Assadi-Porter
Keyword(s):  
Structure Function ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Sweet Taste Receptor

Interaction of suosan with the sweet taste receptor

1982 ◽  
Vol 175 (4) ◽  
pp. 266-268 ◽  
Author(s):  
Jean-Marie Tinti ◽  
Claude Nofre ◽  
Anne-Marie Peytavi
Keyword(s):  
Taste Receptor ◽  
Sweet Taste ◽  
Sweet Taste Receptor

scholarly journals Transformation of postingestive glucose responses after deletion of sweet taste receptor subunits or gastric bypass surgery

2012 ◽  
Vol 303 (4) ◽  
pp. E464-E474 ◽  
Author(s):  
Maartje C. P. Geraedts ◽  
Tatsuyuki Takahashi ◽  
Stephan Vigues ◽  
Michele L. Markwardt ◽  
Andongfac Nkobena ◽  
...  
Keyword(s):  
Gastric Bypass ◽  
Glycemic Control ◽  
Large Intestine ◽  
Molecular Mechanisms ◽  
Hormone Secretion ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Oral Glucose ◽  
Isolated Pancreatic Islets ◽  
Sweet Taste Receptor

The glucose-dependent secretion of the insulinotropic hormone glucagon-like peptide-1 (GLP-1) is a critical step in the regulation of glucose homeostasis. Two molecular mechanisms have separately been suggested as the primary mediator of intestinal glucose-stimulated GLP-1 secretion (GSGS): one is a metabotropic mechanism requiring the sweet taste receptor type 2 (T1R2) + type 3 (T1R3) while the second is a metabolic mechanism requiring ATP-sensitive K+(KATP) channels. By quantifying sugar-stimulated hormone secretion in receptor knockout mice and in rats receiving Roux-en-Y gastric bypass (RYGB), we found that both of these mechanisms contribute to GSGS; however, the mechanisms exhibit different selectivity, regulation, and localization. T1R3−/−mice showed impaired glucose and insulin homeostasis during an oral glucose challenge as well as slowed insulin granule exocytosis from isolated pancreatic islets. Glucose, fructose, and sucralose evoked GLP-1 secretion from T1R3+/+, but not T1R3−/−, ileum explants; this secretion was not mimicked by the KATPchannel blocker glibenclamide. T1R2−/−mice showed normal glycemic control and partial small intestine GSGS, suggesting that T1R3 can mediate GSGS without T1R2. Robust GSGS that was KATPchannel-dependent and glucose-specific emerged in the large intestine of T1R3−/−mice and RYGB rats in association with elevated fecal carbohydrate throughout the distal gut. Our results demonstrate that the small and large intestines utilize distinct mechanisms for GSGS and suggest novel large intestine targets that could mimic the improved glycemic control seen after RYGB.

scholarly journals Ultimate Molecular Theory of Bitter Taste

2021 ◽  
Author(s):  
Huazhong He
Keyword(s):  
Binding Sites ◽  
Bitter Taste ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Receptor Protein ◽  
Helical Structures ◽  
Sweet Taste Receptor ◽  
Multiple Binding Sites ◽  
Multiple Receptors ◽  
Multiple Binding

More than thirty years ago, I proposed a theory about sweet and bitter molecules’ recognition by protein helical structures. Unfortunately the papers could not go to public platform until now. Inspired by the sweet taste theory<sup>1,2</sup>, this bitter taste theory conveys that bitter molecules are recognized by receptor protein helical structures. The recognition process is a dynamic action, in which the receptor protein helices have a torsion-spring-like oscillation between helical structures of 3.6 and 4 amino acids per turn. Based on the characteristics of the bitter receptor protein helix oscillation, it perfectly explains why in bitter molecules, only one unit of hydrogen donor (DH) or hydrogen acceptor (B) is enough in helping molecules to elicit bitter taste. The potential DH and B in bitter receptor are any NH or O of receptor’s peptide NHs and Os, which are the ones forming intramolecular H-bonds responsible for the formation of receptor protein helical structures. Furthermore, only one unit of DH or B is allowed for structurally simple ligands. As recognition sites are only associated with a small fraction – helix structure of whole bitter receptor, multiple binding sites or multiple receptors are well expected. As the oscillation may have different extent, it translates to bitterness intensity. According to ligand-receptor binding motion, bitter receptor could be divided into two kinds of spaces, which are similar to the situation in sweet taste receptor: main and side grooves. These have been discussed in context and especially great details in paper titled deciphering aspartyl peptide sweeteners <sup>2</sup>.

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