User:Fujr Ibrahim/Sandbox 1: Difference between revisions
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== <h4><span style="color: #800020;"> Miraculin’s interactions with human tongue receptors </span></h4> == | == <h4><span style="color: #800020;"> Miraculin’s interactions with human tongue receptors </span></h4> == | ||
Taste processing is a complex process and is initially achieved by the activation of taste receptor | |||
cells clustered on the tongue’s taste buds. Once activated by a wide variety of ligands, the taste | |||
receptor cells transmit signals to parts of the brain that are involved in taste perception <ref> PMID: | |||
28672790 </ref> | |||
Like many interactions involving the binding of a ligand to a receptor, miraculin undergoes a | |||
conformational change when binding to the tongue receptors where its active site shifts to better | |||
bind to tongue receptors <ref> https://doi.org/10.1142/6389 </ref>. | |||
Miraculin binds to the tongue’s HT1R2-HT1R3 (human taste type 1 receptor 2 and 3) receptors | |||
in a pH-dependent manner. HT1R2-HT1R3 is a G-protein coupled receptor that is also capable | |||
of binding to natural sugars and artificial sweeteners. | |||
Recent studies suggested also that the association of the closed and open forms of monomers | |||
constituting the T1R2 T1R3 heterodimer can create a large charged cavity where sweet proteins | |||
fit exerting their function <ref>PMID: 16107151</ref>. Interestingly, although miraculin is inactive at | |||
very basic conditions, it still capable of suppressing the response of HT1R2-HT1R3 to other | |||
sweet-tasting compounds at neutral pH. At acidic conditions, miraculin enhances | |||
HT1R2-HT1R3’s response to sweet-tasting compounds. <ref> | |||
https://www.pnas.org/content/108/40/16819 </ref> Two histidine residues, His30 and His60, participate in | |||
the process of taste-modification. One site maintains the attachment of the protein to the | |||
membranes while the other activates the sweet receptor membrane in acidic conditions. | |||
<ref> https://www.sciencedirect.com/science/article/abs/pii/S0006291X07013010?via%3Dihub </ref> | |||
Although the detailed mechanism of the taste-deceiving protein is unknown, numerous sources | |||
agree to the fact miraculin is activated in the presence of an acidic compound. At an acidic pH, | |||
miraculin assumes an open conformation, similar to that predicted in | |||
fig1 | |||
that permits it to bind | |||
to the tongue’s HT1R2-HT1R3 receptors. | |||
Miraculin is denatured at high temperatures and at pHs below 3 or above 12. The denaturation at | |||
these conditions is most likely due to the loss of shape of the protein and the disruption of bonds | |||
critical to its functionality. | |||
== <h4><span style="color: #800020;"> Miraculin-Like Proteins (MLPs) </span></h4> == | == <h4><span style="color: #800020;"> Miraculin-Like Proteins (MLPs) </span></h4> == | ||
