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 2F o-F c maps around the retinal-Lys216 chain (A) and the proton-release group (B), contoured at 1 σ and overlaid on the structural model. Carbon, oxygen and nitrogen atoms are drawn in green, red and blue, respectively.
