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Protocols for M13KO7 Helper Phage FAQs for Nucleic Acids Technical Reference for Nucleic Acids Enzyme Finder NEBcutter NEBuffer Chart Double Digest Finder Isoschizomers DNA Sequences and Maps REBASE

Home > Products > Nucleic Acids > Phage DNAs > M13KO7 Helper Phage M13KO7 Helper Phage Catalog # Size Concentration Price Qty   N0315S 1.8 ml 1 x1011 pfu/ml $61.00 Prices are in US dollars and valid only for US orders. Download: MSDS PDF Description: M13KO7 is an M13 derivative which carries the mutation Met40Ile in gII, with the origin of replication from P15A and the kanamycin resistance gene from Tn903 both inserted within the M13 origin of replication (1). M13KO7 is able to replicate in the absence of phagemid DNA. In the presence of a phagemid bearing a wild-type M13 or f1 origin, single-stranded phagemid is packaged preferentially and secreted into the culture medium.This allows easy production of single-stranded phagemid DNA for mutagenesis or sequencing. Source: M13KO7 phage supernatant was isolated from infected E. coli ER2738 by a standard procedure (2). Reaction & Storage Conditions Concentration: 1 x1011 pfu/ml Storage Temperature: -20°C Quality Control for Current Lot Quality control values for a specific lot can be found on the datacard which accompanies each product. Absolute titer: Infection of a mid-log culture of E. coli ER2690 followed by plating yielded 1.0 x 1011 pfu/ml. Viable cell titer: Plating the phage suspension for viable cells on LB agar yielded a titer of < 102/ml. Helper ratio: Superinfection of an early-log culture of E. coli ER2738/pLITMUS 38 with 3 x 108 pfu/ml M13KO7, followed by incubation for 18 hours in the presence of 70 µg /ml kanamycin, yielded a supernatant that was tested for relative titers of packaged helper phage vs. phagemid as follows: The supernatant was heated at 65°C to kill any viable cells. A mid-log culture of E. coli ER2690 was briefly incubated with diluted supernatant and then plated both for plaques (to determine M13KO7 titer) and colonies on ampicillin plates (to determine packaged pLITMUS 38 titer). The ratio of ampicillin-resistant colonies to plaques was 10:1. Agarose gel electrophoresis confirmed a 10-fold excess of packaged phagemid DNA over helper phage. References Vieira, J. and Messing, J. (1987) R. Wu and L. Grossman (Eds.), Methods Enzymol., 153, pp. 3-11. San Diego: Academic Press. Sambrook, J. and Russell, D.W. (2001) Molecular Cloning: A Laboratory Manual (3rd Ed.), 3.17-3.32.