5 marks 1a Th e dissociation constant for the binding of the

5 marks

1.(a) Th e dissociation constant for the binding of the ligand to a GPCR is 10^-10 M.It was found that ligand binding to only 10% of the around 1000 GPCRs on the cell is required for the maximal activation of the G protein.Calculate what is the ligand concentration required to bring about the maximal activation.

Solution

1a)the ligand concentration = K(d)/1000*10%

=(10^-10/1000)* 10/100

=>10^-14 L

2)The ligand bonding will decrease as it will get streched to increase the affinity to GTP.

IF the mutant G-proteins are being treated with a non-hydrolyzable analog of GTP then the ligand bonding will increase and the analog of GTP increases the number of bonds between ligands by increae in carbon atoms. and sub alpha and beta units.