Protein folding in vitro and in the cellular environment

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Protein folding is crucial for cellular function.
• In vitro studies suggested folding is spontaneous, driven by amino acid sequence and thermodynamics.
• The discovery of molecular chaperones necessitates a re-evaluation of intracellular protein folding mechanisms.

Purpose of the Study:

• To review the role of molecular chaperones in protein folding within the cell.
• To discuss the mechanisms by which molecular chaperones assist protein folding and assembly.
• To highlight the current understanding and knowledge gaps in chaperone-mediated protein folding.

Main Methods:

• Literature review of in vitro and in vivo protein folding studies.
• Analysis of data on molecular chaperone function and mechanisms.
• Discussion of the 'molten globule' state in relation to chaperone binding.

Main Results:

• Molecular chaperones actively mediate protein folding and subunit assembly in vivo.
• Chaperones prevent premature folding, misfolding, and aggregation of polypeptide chains.
• Chaperones interact with incompletely folded proteins, often in the 'molten globule' state.

Conclusions:

• Intracellular protein folding is actively regulated by molecular chaperones, not solely spontaneous.
• Molecular chaperones play a vital role in maintaining proteostasis by preventing protein misfolding.
• Further research is needed to elucidate the precise recognition mechanisms of molecular chaperones.