Electrophoretic mobility of λ phage HIND III and HAE III DNA fragments in agarose gels: A detailed study
✍ Scribed by H. Hervet; C. P. Bean
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1987
- Tongue
- English
- Weight
- 834 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
The electrophoretic mobility ( p ) of DNA fragments from X phage and @X 174, split by restriction enzyme to molecular lengths from 3 X lo2 to 2.36 X lo4 base pairs, has been investigated in 0.6-41 agar-gels at various field strengths, ionic strengths, and temperatures.
As already observed, p is seen to be very sensitive to the field, increasing with field strength. The sensitivity increases with the molecular length of the DNA and decreases at high gel concentration. Our data are in qualitative agreement with recent theoretical predictions that concern the influence of the electric field on electrophoretic mobility. Mobility data have been extrapolated to zero field. This enables a comparison of our experimental results with theoretical predictions on the dependence of p on the molecular weight of the DNA fragments. Our data fit, quite closely, a reptation model, where the tube path is described as a semiflexible entity with a persistence length equal to the pore diameter. The influence of the agarm concentration and the ionic strength of the buffer on the two parameters of the model-intrinsic electrophoretic mobility ( p o ) and the number of base pairs per element of the tube (g)-are well described by the model. The temperature dependence of the electrophoretic mobility, together with the influence of the agar-concentration on po, indicate that the hydrodynamic drag is the leading frictional force on the DNA molecules in the gel.