Dissipative dynamics of enzymes.

Area of Science:

• Biophysics
• Enzymology
• Structural Biology

Background:

• Enzyme function is intrinsically linked to their conformational dynamics.
• Understanding how temperature affects these dynamics is crucial for enzyme activity and stability.
• Previous studies have explored enzyme mechanics, but sub-Å resolution temperature effects remain less understood.

Purpose of the Study:

• To investigate enzyme conformational dynamics at sub-Ångström resolution.
• To determine the effect of temperature on the mechanical response of folded enzymes.
• To characterize the viscoelastic properties of enzymes across a temperature range.

Main Methods:

• Utilized sub-Ångström resolution techniques to probe enzyme conformational dynamics.
• Applied a viscoelastic model to describe the ensemble-averaged mechanical response.
• Conducted experiments across a temperature range from 10°C to 45°C.
• Performed equilibrium mechanical experiments using a DNA spring and a different enzyme for comparison.

Main Results:

• Enzyme mechanical response is viscoelastic between warm and cold denaturation transitions.
• Dissipation parameter (γ) and elastic parameter (K) both decrease by a factor of 2 as temperature increases from 10°C to 45°C.
• Enzymes dynamically soften with increasing temperature.
• Equilibrium experiments qualitatively confirmed enzyme softening with rising temperature.

Conclusions:

• Enzymes exhibit temperature-dependent viscoelastic behavior.
• Increasing temperature leads to a softening of the enzyme's mechanical properties.
• These findings provide new insights into enzyme dynamics and their response to thermal changes.