The case for intrinsically disordered proteins playing contributory roles in molecular recognition without a stable...

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Biology

Background:

• Classical binding models (lock-and-key, induced-fit) emphasize substrate-catalyst complementarity, derived from enzyme catalysis.
• These models inherently bias towards mechanisms requiring specific 3D structure.
• Relaxation of structural requirements occurs when binding, not catalysis, is the primary endpoint.

Purpose of the Study:

• To explore binding mechanisms beyond strict structural complementarity.
• To discuss the role of intrinsically disordered proteins (IDPs) in biological functions.
• To re-evaluate the concept of IDPs in molecular recognition and function.

Main Methods:

• Review of existing literature on protein binding mechanisms.
• Analysis of recent experimental observations on non-canonical binding.
• Discussion of theoretical frameworks for molecular recognition.

Main Results:

• Binding without catalysis can involve a significant lack of specific 3D structure.
• Molecular recognition can depend on kinetic, entropic, and generalized electrostatic effects, not just structural complementarity.
• Unstructured protein regions perform biological functions independent of molecular recognition.

Conclusions:

• Established binding models are insufficient for interactions lacking fixed structures.
• Intrinsically disordered proteins represent a paradigm shift in understanding protein function and molecular recognition.
• The concept of intrinsically disordered proteins (IDPs) warrants further investigation and may be a useful framework.