PPi(from ATP) a NH时+R-0-P-0Rboe Adenine Riboee Adenine or 0 NMN (from NAD*) 0 DNA ligase AMP from ATP (R PP Enzyme-AMP or NAD*(R NMN) Ribose Adenine It b Tt LLOH 0 0山山000山 Enzyme-AMP 001 0 0 Nick in DNA 0 0 Ribose Adenine 0 DNA ligase TTTTTT O+0-P-0-Ribose Adenine 山o-0山 0 0 AMP Sealed DNA 0 O-Ribose Adenine Figure 24-15 The mechanism of the DNA ligase