The vanilloid receptor TRPV1 detects temperatures in the range of 40 to 50°C. We
ID: 3483055 • Letter: T
Question
The vanilloid receptor TRPV1 detects temperatures in the range of 40 to 50°C. We said that such a responsiveness requires large enthalpy and entropy changes between closed and open states. Justify the argument by plotting the relationship of channel opening versus 1/T (T in kelvin) with different values of enthalpy DH) and entropy (DS) changes. What are the least values of DH and DS for TRPV1? The vanilloid receptor TRPV1 detects temperatures in the range of 40 to 50°C. We said that such a responsiveness requires large enthalpy and entropy changes between closed and open states. Justify the argument by plotting the relationship of channel opening versus 1/T (T in kelvin) with different values of enthalpy DH) and entropy (DS) changes. What are the least values of DH and DS for TRPV1?Explanation / Answer
ANS) The trpv1 channel plays an important position in producing nociceptive alerts in mammalian primary sensory neurons. it includes 838 amino acids with six transmembrane segments (tm1-tm6), a pore-forming loop among tm5 and tm6 and n- and c- terminals placed intracellularly. it is a homotetramer and paperwork a nonselective cationic channel that can be opened with the aid of capsaicin, weak acids and noxious heat. there are 18 cysteines (cys), 3 of that are located on the extracellular facet of the receptor in and across the area of the pore-forming loop. we report that the trpv1 channel in transfected hek293t cells and in cultured rat drg neurons is blocked inside the open kingdom through an oxidizing agent cu-o-phenanthroline complicated (cu:phe). the effects of cu:phe are awareness structured ( ic50 = 5.2 : 20.eight microm ) and completely reversible. cu:phe implemented straight away earlier than exposure to an acidic solution, capsaicin or noxious warmth is without impact. substitutions of the extracellular cys residues (616, 621, 634) by glycine in my opinion or collectively do now not adjust the blockading outcomes of cu:phe suggesting that disulfide move-linking does no longer represent the underlying mechanism. it's miles counseled that the complicated cu:phe, a cumbersome, positively charged molecule, represents a totally effective and reversible open channel blocker of trpv1.
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