In the above figure PKA is shown in blue and 2CSN in grey. In PKA the glycine rich loop is in light blue, the phosphate anchor in a darker blue, the catalytic loop in yellow and the THR 197 phosphoylation site a green sphere.

While there are peripheral differences between these two structures, the overall topology of the functional regions are similar. PKA exhibits a slightly more open conformation with the small top lobe twisted away