Trimethylamine N-oxide (TMAO) enhances substrate mechanical stability probed by single molecule magnetic tweezers

Abstract

Trimethylamine N-oxide (TMAO) is a well-known osmolyte to stabilize the folded proteins through a variety of mechanisms. Since mechanical strength of proteins is a critical determinant of its stabilization, TMAO might play a relevant role by favoring its folding dynamics or by enhancing its mechanical stability. To address this question, we have performed the single-molecule magnetic tweezers experiment to explore the TMAO effect on two structurally distinct substrates-protein L and talin. We observed that TMAO increases the mechanical stability of these proteins through increasing their unfolding force. Additionally, we are able to demonstrate that TMAO retards the unfolding kinetics, while accelerating the refolding kinetics under force; which eventually tilts the energy landscape towards the folded state. Interestingly, this TMAO-enhanced protein folding generates mechanical work output upto ∼67 zJ, allowing the protein folding under higher force regime. Overall this TMAO-enhanced mechanical stability provides a significant implication to folding-induced structural stability of proteins.

Trimethylamine N-Oxide (TMAO): a Unique Counteracting Osmolyte?

“…• Chaudhuri et al [58]. using magnetic tweezers spectroscopy on Protein L, found that TMAO increases protein mechanical stability by increasing the the force need for unfolding, slowing unfolding and accelerating folding kinetics.…”