A new form of DNA polymerase 3 and a copolymerase replicate a long, single-stranded primer-template.


A new form of DNA polymerase III, termed Pol III star (Pol III(*)), has been purified to homogeneity from Escherichia coli. Pol III(*) is temperature sensitive when isolated from a thermo-sensitive dnaE mutant, as had been described for Pol III. Pol III(*) and Pol III are separable by gel filtration. Pol III(*) utilizes a duplex template containing short gaps with the same catalytic properties as Pol III. However, Pol III(*) is able to replicate long, singlestranded templates such as homopolymer chains and viral circles of M13 and varphiX174 if provided with the following: spermidine, a primer fragment, and a new protein, termed copolymerase III(*) (Copol III(*)). The latter, purified to homogeneity, has no known independent enzymatic activity and supports synthesis by Pol III(*) but not by Pol I, Pol II, or Pol III.



Historical Protein Properties (MW, pI, ...), Accessory Proteins/Complexes, Other Enzymatic Activities, Nucleotide Incorporation, Modulators/Inhibitors


new topics/pols set partial results complete validated


Polymerase Reference Property Result Context
Eco Pol III* Wickner W1973 Extension from RNA primer Yes
Eco Pol III* Wickner W1973 Specific Activity 1800 units/mg
Eco Pol III* Wickner W1973 Nucleotide incorporation accessory protein(s) copolymerase III*
Eco Pol III* Wickner W1973 Percent/Fold Effect 99 % decrease Reaction: Nucleotide incorporation; Substrate: dNTPs; Experimental conditions: Spermidine (0mM)
Eco Pol III* Wickner W1973 Gap Filling Yes

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