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.
A diagram of a hypothetical macromolecular system. P consists of the atoms with known protonation state and geometry, A1, A2, and A3 denote chemical groups of atoms for which the protonation state is unknown; each group has a finite number of alternative states consisting of combinations of ionization, tautomer, flip, and rotamer configurations; in the diagram: four states for A1, two states for A2, and three states for A3.
