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G protein coupled receptor

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G protein coupled receptor

Postby th1_rhs13 » Thu Dec 08, 2005 5:21 am

Right, Im at a loss with these questions and Im kinda dead from Lab finals:

Diagrams
-How G protein coupled receptor acticates G-ptotein.
-Structure of Atp Synthase.


Literal

-How does G protein coupled receptor actvate Protein kinase A,C?

Much obliguied, I need sleep.

EDIT: Im lame, I just looked thorugh my notes and saw the G protein.

But ATP synthase is still mystery...
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Postby sdekivit » Thu Dec 08, 2005 10:35 am

G-coupled receptors are the so called serpentinereceptors or also called the 7-alfa-helixreceptors.

When they bind a ligand, the hetrimeric G-protein binds to it, and underogoes a conformational change so that GDP is exchanged for GTP.

--> the receptor acts like a GEF (guanine nucleotide exchange factor)

then de alfa-subunit dissociates from the beta/gamma-subunit of the G-protein

--> the alfa subunit can activate adenylyl cyclase for example by a conformational change so that adenylyl cyclase produces cAMP out of ATP.

--> cAMP is a second messenger that binds to the regulatory subunits of PKA and these dissociate, leaving active PKA subunits to go into the nucleus and activate for exampel transcription.

The alfa-subunit hydrolyses its GTP through intrinsic GTPase activity and reassociates to form the heterotrimeric G-protein.
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Postby th1_rhs13 » Fri Dec 09, 2005 1:05 am

Thank you, however I found my diagram depciting such, my emphasis is now focused on the neccessity to address ATP synthase, perferasbbly a diagram as I must have missed that lecture.
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Postby th1_rhs13 » Fri Dec 09, 2005 10:48 am

Image

All right can anyone brief me on the significance of the alpha, beta and gamma sturtures within F1, and the lower component of F0. Perhaps the Hydrogen molecules that surround it?
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Postby kaylin » Sat Dec 10, 2005 4:00 pm

G protein is divided by 2 types. there are: Gs(stimulate), and Gi(ingibition)

G protein is consist of alpha, betta and gamma polepeptide

alpha is GTP

i've got some language problem :(
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Postby sdekivit » Sat Dec 10, 2005 4:38 pm

kaylin wrote:G protein is divided by 2 types. there are: Gs(stimulate), and Gi(ingibition)

G protein is consist of alpha, betta and gamma polepeptide

alpha is GTP

i've got some language problem :(


there are more types of G-proteins ;)
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