This C-terminal capping motif is called the Schellman motif or loop*

The H-bonds in white are within the alpha-helix from the CO groups of residues 3,4,5,6 to the NH groups of residues 7,8,9,10.

The capping motif is a pair of H-bonds from the NH of residue 11 to the CO of residue 8, and from the NH of residue 12 to the CO of residue 7. These H-bonds are colored yellow.

(PubMed)

351c (PDB)

Schellman, C. 1980. The αL conformation at the ends of helices. In Protein Folding (ed. R. Jaenicke), pp. 53–61. North-Holland Biomedical Press, Elsevier, Amsterdam.