Single-molecule microscopy reveals new insights into nucleotide selection by DNA polymerase I.


The mechanism by which DNA polymerases achieve their extraordinary ...
The mechanism by which DNA polymerases achieve their extraordinary accuracy has been intensely studied because of the linkage between this process and mutagenesis and carcinogenesis. Here, we have used single-molecule fluorescence microscopy to study the process of nucleotide selection and exonuclease action. Our results show that the binding of Escherichia coli DNA polymerase I (Klenow fragment) to a primer-template is stabilized by the presence of the next correct dNTP, even in the presence of a large excess of the other dNTPs and rNTPs. These results are consistent with a model where nucleotide selection occurs in the open complex prior to the formation of a closed ternary complex. Our assay can also distinguish between primer binding to the polymerase or exonuclease domain and, contrary to ensemble-averaged studies, we find that stable exonuclease binding only occurs with a mismatched primer terminus.



Kinetic Parameters, Nucleotide Incorporation


new topics/pols set partial results complete validated


No results available for this paper.

Entry validated by:

Using Polbase tables:


Tables may be sorted by clicking on any of the column titles. A second click reverses the sort order. <Ctrl> + click on the column titles to sort by more than one column (e.g. family then name).


It is also possible to filter the table by typing into the search box above the table. This will instantly hide lines from the table that do not contain your search text.