Sandbox Reserved 1167: Difference between revisions

From Proteopedia
Jump to navigationJump to search
No edit summary
No edit summary
Line 16: Line 16:
=== Class B vs. Class A ===
=== Class B vs. Class A ===


Like all classes of glucagon receptors, which include class A ([https://en.wikipedia.org/wiki/Rhodopsin-like_receptors rhodopsin-like]), B (secretin-like), and [https://en.wikipedia.org/wiki/Class_C_GPCR C] ([https://en.wikipedia.org/wiki/Metabotropic_glutamate_receptor metabotropic glutamate]), GCGR has a 7tm domain. While class B receptors do share characteristics with class C receptors, they are more similar to class A receptors. Class B receptors and class A receptors share less than 15% sequence [https://en.wikipedia.org/wiki/Homology_(biology) homology]; however, they do share similar [https://en.wikipedia.org/wiki/Signal_transduction signal transduction] mechanisms as well as the 7tm domain. The orientations and positions of the 7tm helices are also conserved between both classes of glucagon receptors.  
Like all classes of glucagon receptors, which include class A ([https://en.wikipedia.org/wiki/Rhodopsin-like_receptors rhodopsin-like]), B (secretin-like), and [https://en.wikipedia.org/wiki/Class_C_GPCR C] ([https://en.wikipedia.org/wiki/Metabotropic_glutamate_receptor metabotropic glutamate]), GCGR has a 7tm domain. While class B receptors do share characteristics with class C receptors, they are more similar to class A receptors. Class B receptors and class A receptors share less than 15% sequence [https://en.wikipedia.org/wiki/Homology_(biology) homology]; however, they do share similar [https://en.wikipedia.org/wiki/Signal_transduction signal transduction] mechanisms as well as the 7tm domain. The orientations and positions of the 7tm helices are also conserved between both classes of glucagon receptors<ref name ='structure_article'>PMID:23863937</ref>.  


However, one particular difference between class A receptors and class B receptors is an inward shift of the intracellular component of Helix VII. In class A receptors this inward shift is instrumental in receptor activation, yet in class B receptors it remains unclear what role this shift plays.  
However, one particular difference between class A receptors and class B receptors is an inward shift of the intracellular component of Helix VII. In class A receptors this inward shift is instrumental in receptor activation, yet in class B receptors it remains unclear what role this shift plays<ref name ='structure_article'>PMID:23863937</ref>.  
    
    
In contrast to class A glucagon receptors which have a [https://en.wikipedia.org/wiki/Proline proline] kink, in all  [https://en.wikipedia.org/wiki/Secretin_receptor_family secretin-like class B glucagon receptors] a [https://en.wikipedia.org/wiki/Glycine Glycine] at position 393 in Helix VII allows for a <scene name='72/721537/Gly_393_helical_bend/1'>helical bend</scene>. This glycine helical bend is fully [https://en.wikipedia.org/wiki/Conserved_sequence conserved] in all secretin-like class B receptors.
In contrast to class A glucagon receptors which have a [https://en.wikipedia.org/wiki/Proline proline] kink, in all  [https://en.wikipedia.org/wiki/Secretin_receptor_family secretin-like class B glucagon receptors] a [https://en.wikipedia.org/wiki/Glycine Glycine] at position 393 in Helix VII allows for a <scene name='72/721537/Gly_393_helical_bend/1'>helical bend</scene>. This glycine helical bend is fully [https://en.wikipedia.org/wiki/Conserved_sequence conserved] in all secretin-like class B receptors.