FEBS J. 2005 Dec;272(23):5991-6000

Kuhn H, Frank-Kamenetskii MD.

Template-independent ligation of single-stranded DNA by T4 DNA ligase.

The yield of blunt dsDNA - ssDNA ligation is 200 times lower than blunt dsDNA - dsDNA ligation when the 5′-phospate is on the dsDNA side.