An official website of the United States government
Here's how you know
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.
Structures of the natural and unnatural amino acids used in this study. Carbon numbers for C3, C4, and C5 are highlighted on the phenylalanine structure.