Fig. 105: The ground state of carbon monoxy myoglobin MbCO. The protein is shown in two ways: on the left, helixes are represented by ribbons, the heme is shown in red and the CO is green and black. On the right the atoms are represented by their the Van der Waals radii. Note that the CO is hidden in the protein interior. The ability of the CO to exit the heme pocket illustrates that protein structure is not static but dynamic with channels opening and closing.