kevinsuper

Apparently, for dna synthesis between circular dna and linear dna, T4 phage gp43 Pol allows for dna synthesis to commence WITHOUT prior addition of a primer, whereas the primer is required for circular dna. As a comparison, a test run with DNA Pol III demonstrated that the primer is required in both cases for that enzyme. In a kinetic plot of linear dna synthesis with and without a primer, it is evident that synthesis with primer is faster, while synthesis without the primer has an initial retarded period, followed by a slower rate of synthesis. Is there some kind of physiological/structural difference going from circular to linear dna that allows gp-43 Pol. to synthesize dna without a primer?

After I read the valuable replies from all of you,I've still got some confusions~~~

Here is the question.I don't even know how to approach~~~Thanks for detailed help!Please be Specific! Three lacZ-E.Coli strains which have nonsense mutations each one.i.e 5'TAA,TAG and TGA.You wish to convert each of nonsense one to sense and choose UV irradiation to revert them.Using the knowledge of lesion bypass by DNA ploymerase V and the "A-rule" show the expected results for each nonsense mustions.Do the results suggest if UV is effective for converting nonsense to sense?Be specific!Thanks a lot!