Structural bases of a long-stretched deletion: completing the lambda plac5 DNA primary structure

PCR amplification of up to 35-kb DNA with high fidelity and high yield from lambda bacteriophage templates

A target length limitation to PCR amplification of DNA has been identified and addressed. Concomitantly, the base-pair fidelity, the ability to use PCR products as primers, and the maximum yield of target fragment were increased. These improvements were achieved by the combination of a high level of an exonuclease-free, N-terminal deletion mutant of Taq DNA polymerase, Klentaq1, with a very low level of a thermostable DNA polymerase exhibiting a 3'-exonuclease activity (Pfu, Vent, or Deep Vent). At least 35 kb can be amplified to high yields from 1 ng of lambda DNA template.

Lambda plac10 transducing bacteriophage: DNA primary structure of the region of the abnormal excision

In studying molecular mechanisms of the formation of transducing bacteriophages, we have elucidated the primary structure of the phage-bacterial DNA junction which resulted from the abnormal excision of the lambda plac10 phage. The process is structurally similar to the excision of the lambda plac5 phage and involves, in both cases, highly homological DNA stretches approximately 20 bp long, one of them being a part of the Z-Y spacer of the lac operon and possessing a developed secondary structure. The conception of regioselective recombination as a type of illegitimate recombinational process with a certain degree of site-specificity is suggested.