Comment on "Flexibility of short DNA helices with finite-length effect: From base pairs to tens of base pairs" [J. Chem. Phys. 142, 125103 (2015)].

As expected, the asymptotic persistence lengths are the same in these two cases, as both converge toward the same HT <math display="inline" overflow="scroll" xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow> l </mrow><mrow><mtext>B,T</mtext></mrow><mrow> </mrow></msubsup></math> ht for large m. However, the I B i SB I i sb are determined by the boundary contributions of short segments (small m). This relation holds approximately for the values reported by Wu I et al. i :[1] HT <math display="inline" overflow="scroll" xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow> l </mrow><mrow> B </mrow><mrow> </mrow></msubsup><mo>=</mo><mn>50</mn></math> ht nm, I A i = 450 nm, and I B i = 10. Note that expression (2) contains one parameter less than (1), implying that HT <math display="inline" overflow="scroll" xmlns="http://www.w3.org/1998/Math/MathML"> A <mo>=</mo><msubsup><mrow> l </mrow><mrow> B </mrow><mrow> </mrow></msubsup> B </math> ht . [Extracted from the article]