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.
The first three levels of the CATH structure classification hierarchy: Class (based on secondary structure content), Architecture (based on gross spatial arrangement of secondary structures), Topology or Fold (similar folding arrangement of secondary structures).
