A major group of G protein-linked receptors contain seven transmembrane alpha helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others.
The coupled G protein most likely interacts with this receptor
a.at the COO- end
b.at the NH3 end
c.at the loop between H5 and H6
d.along the exterior margin
e.along the interior margin