Description:
Duplex DNA is isolated from bacteriophage lambda (cI857ind 1 Sam 7). The bacteriophage is grown in an E. coli host which is deficient in adenine methylase (dam
-). Therefore, those deoxyadenosine positions which are methylated in a wild type E. coli host are not methylated in the dam
- host. This DNA gives complete digests with restriction endonucleases that are sensitive to dam methylation. Lambda DNA (N
6-methyladenine-free) is 48,502 base pairs in length.
Source
The phage is isolated from a heat-inducible E. coli(dam-) lambda lysogen. The DNA is isolated frompurified phage by phenol extraction and dialyzed against 10 mM Tris-HCl (pH 8.0)and 1 mM EDTA.Notes:
The advantage of this DNA is that it gives complete digests with those restriction endonucleases (BclI, MboI, DpnII, etc.) whose recognition sites are partially modified by most E. coli strains.
