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.
Force-extension curve of double-stranded λ-DNA. While retracting the cantilever from the surface with a velocity of 16 μm/s the double-stranded λ-DNA is stretched. At a force between 65 and 70 pN the well-known highly cooperative B-S transition is observed. During this transition the DNA duplex lengthens by a factor of 1.7. After this transition the force increases to a value of ∼170 pN where the DNA finally ruptures.
