Functional roles of slow enzyme conformational changes in network dynamics

Area of Science:

• Biophysics
• Systems Biology
• Enzymology

Background:

• Macromolecules, particularly enzymes, exhibit slow conformational transitions, referred to as dynamic disorder or hysteresis.
• Recent single-molecule enzymology and NMR studies have provided direct evidence for these slow conformational dynamics.

Purpose of the Study:

• To analyze the role of enzyme slow conformational changes within regulatory networks.
• To explore how these dynamics contribute to network properties like noise filtering and adaptive responses.

Main Methods:

• Analysis of enzyme kinetics within regulatory network contexts.
• Examination of specific examples including enzymes responding to pH fluctuations and metabolic changes.
• Theoretical modeling of enzyme conformational dynamics as functional network motifs.

Main Results:

• A single enzyme with slow conformational changes can filter upstream network noise.
• Such enzymes can exhibit resonant responses to stimuli at specific frequencies or adaptive responses to sustained signals.
• These enzymes can function as basic building blocks for synthetic networks, providing properties like narrow-band filtering.

Conclusions:

• Enzyme slow conformational dynamics represent a fundamental functional motif in biological networks.
• The coupling between enzyme biophysics and network dynamics is functionally significant.
• Conformational dynamics of enzymes may have been evolutionarily selected for their network-level functions.