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) Modes by which PNA may recognize double-stranded DNA. (B) Schematic drawing of adenine⋅thymine, diaminopurine⋅thymine, diaminopurine⋅thiouracil, and adenine⋅thiouracil base pairs showing how diaminopurine can form an extra hydrogen bond with thymine, whereas a steric clash occurs between diaminopurine and thiouracil.
