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Can energy landscape roughness of proteins and RNA be measured by using mechanical unfolding experiments? (PNAS '03) By considering temperature effects on the mechanical unfolding rates of
proteins and RNA, whose energy landscape is rugged, the question posed in the
title is answered in the affirmative. Adopting a theory by Zwanzig [Zwanzig,
R. (1988) Proc. Natl. Acad. Sci. USA 85, 2029-2030], we show that,
because of roughness characterized by an energy scale |
, the unfolding
rate at constant force is retarded. Similarly, in nonequilibrium experiments
done at constant loading rates, the most probable unfolding force increases
because of energy landscape roughness. The effects are dramatic at low
temperatures. Our analysis suggests that, by using temperature as a variable
in mechanical unfolding experiments of proteins and RNA, the ruggedness energy
scale