Can somebody help me with a point in this paper? On page 5326, near the top of the right hand column, the authors say, "Analyses to date, including our work, imply that duplex stabilisation by 5mC is predominantly due to entropic rather than enthalpic effects." However, Figure 3 just above shows marked differences in the enthalpy of the duplex containing 5mC and that containing unmethylated cytidine, that are just as significant as the differences in entropy shown alongside. How, then, are they led to the conclusion that the difference is due to entropic effects and not to enthalpic effects?
Note: PMID 1945840 says that "the effect of substituting, in the stem of hairpin CGCGCGTTTCGCGCG, the cytosines with 5-methylcytosines enhances the Tm from 74° to 82 °C, while the DeltaH of both hairpins is - 213 kJ/mol", which appears to corroborate the authors' statement. #spnetworkwas