Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Illustrations of the hydrogen-bonding network in alpha-helix and beta-sheet secondary structures. (A) Hydrogen-bonding network in alpha-helix; (B and C) possible hydrogen-bonding networks in the same parallel beta-sheet; (D and E) possible hydrogen-bonding networks in the same anti-parallel beta-sheet. Dotted lines denote the hydrogen bonds.
