Why are proteins marginally stable?

Area of Science:

• Protein biochemistry
• Evolutionary biology
• Computational biology

Background:

• Globular proteins typically exhibit marginal stability, irrespective of their size or biological activity.
• Marginal stability is often interpreted as a requirement for protein function, implying it results from positive selection.
• The evolutionary drivers and implications of protein marginal stability remain incompletely understood.

Purpose of the Study:

• To investigate the origins of protein marginal stability using model proteins and population dynamics.
• To determine whether marginal stability is a functional adaptation or an inherent property of protein sequence space.
• To explore the evolutionary advantages of marginal stability in protein populations.

Main Methods:

• Utilized model proteins to study the dynamics of protein evolution within populations.
• Analyzed the relationship between protein sequence space dimensionality and stability.
• Simulated competition between protein sub-populations with varying stability requirements for functionality.

Main Results:

• Protein marginal stability is an intrinsic characteristic arising from the high dimensionality of protein sequence space, independent of function.
• Marginal stability can be a consequence of neutral, non-adaptive evolutionary processes.
• Populations of marginally stable proteins demonstrated a tendency to dominate in simulations, indicating a strong evolutionary advantage.

Conclusions:

• The inherent tendency of proteins towards marginal stability can explain its prevalence, rather than solely adaptive selection for function.
• Functionalities associated with marginal stability possess a significant evolutionary advantage.
• Marginal stability may naturally emerge due to inherent biophysical properties and evolutionary dynamics.