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Updated: Aug 23, 2025
Genetic Variant Detection in the CALR gene using High Resolution Melting Analysis
Published on: August 26, 2020
The melting curves of calf thymus-DNA are buffer specific
Monica Mura1, Cristina Carucci1, Flaminia Cesare Marincola1
1Department of Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, SS 554 bivio Sestu, 09042 Monserrato, CA, Italy; Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), Florence, Italy, Unità Operativa University of Cagliari, Italy.
Abstract:
The specific effects of salts (strong electrolytes) on biomolecular properties have been investigated for more than a century. By contrast, the specific role of pH buffers (weak electrolytes and their salts) has usually been ignored. Here, specific buffer effects on DNA thermal stability were evaluated by measuring the melting curve of calf thymus DNA through UV-vis spectroscopy. The study was carried out using phosphate, Tris, citrate and cacodylate buffers at fixed pH 7.4 at concentrations varying systematically in the range 1-600 mM. DNA stability increases with buffer concentration and is influenced specifically by buffer type. To interpret empirical data, a theoretical model was applied with parameters quantifying the impact of buffer on the DNA backbone charge. Comparing the buffer effects via buffer ionic strength rather than buffer concentration, we find that the buffers stabilize DNA in the order Tris > cacodylate > phosphate > citrate.
