pH-dependent specific binding and combing of DNA

Publication Type:

Journal Article


BIOPHYSICAL JOURNAL, BIOPHYSICAL SOCIETY, Volume 73, Number 4, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998, p.2064-2070 (1997)




Recent developments in the rapid sequencing, mapping, and analysis of DNA rely on the specific binding of DNA to specially treated surfaces. We show here that specific binding of DNA via its unmodified extremities can be achieved on a great variety of surfaces by a judicious choice of the pH. On hydrophobic surfaces the best binding efficiency is reached at a pH of similar to 5.5. At that pH a similar to 40-kbp DNA is 10 times more likely to bind by an extremity than by a midsegment, A model is proposed to account for the differential adsorption of the molecule extremities and midsection as a function of pH. The pH-dependent specific binding can be used to align anchored DNA molecules by a receding meniscus, a process called molecular combing. The resulting properties of the combed molecules will be discussed.