Several glycines are found in the irregular loop between helix G and helix H. These breaker amino acids give the backbone the flexibility needed to form the hairpin. Magnified view of the connecting loop region between helix G and helix H. Ball and stick representation, proline in green and glycine in yellow. The N atom has no hydrogen so can't act as an H bond donor. G on the right. Helices G and H redrawn with spacefilling atoms, now with amino acid side chains made visible.
H are red.
Note how the space between the two helices is well filled by side chains and how the side chains from each helix interlock to give a jigsaw puzzle like fit. The surface visible in front is similarly interlocked with the rest of the protein. This figure shows the whole myoglobin molecule in a cutaway section. Amino acids are drawn with spacefilling atoms, non-polar amino acids in red and polar amino acids in green.