* To whom correspondence should be addressed.
Received April 4, 2008; Revision received June 19, 2008
Bacterial NAD-dependent Taq and Tth DNA ligases are capable of significantly increasing the yield of long PCR products when the amplification is carried out using bacterial family A DNA polymerases, e.g. Taq or Tth DNA polymerases, or with enzymatic blends containing these polymerases. We also show that Taq and Tth DNA ligases improve the results of PCR in the absence of NAD and therefore in the absence of DNA ligase activity. These observations suggest that bacterial DNA ligases can interact with these DNA polymerases, presumably as accessory proteins, thereby enhancing the efficiency of DNA polymerization.
KEY WORDS: long PCR, Taq DNA polymerase, Taq DNA ligase