| Comments |
P.225 right column top paragraph: "These experiments are usually interpreted using the WLC [worm-like chain model] theory of entropic elasticity (ref 1), which predicts the total contour length, ΔLu, of the protein, proportional to the number of unraveled amino acids in the chain. The contour length measured by force-extension experiments is therefore defined as the maximum distance between the mechanically stable transition state and the fully extended state of the linear protein chain with no degrees of freedom. All previous studies using force-extension experiments with an AFM have calculated the contour length as the distance between the native state and the extended state along the reaction coordinate, neglecting the important contribution of the distance up to the transition state (primary sources 2–6,15,16). For this reason, the cited values for the contour length per amino acid, l, vary from protein to protein, spanning from 3.4 Å(primary source 2) to 3.6 Å(primary sources 3,15,16), 3.8 Å(primary sources 4–6), and further up to 4.0 Å(primary source 7)." |