Protein quality control in the bacterial periplasm

Area of Science:

• Bacterial protein export and folding
• Cellular protein trafficking and quality control

Background:

• Extracytoplasmic proteins require proper folding in the correct cellular compartment for function.
• In Escherichia coli, proteins are synthesized in the cytoplasm and exported via specific pathways based on their destination.

Purpose of the Study:

• To summarize general principles governing protein folding in the bacterial periplasm.
• To highlight the role of specific protein components in periplasmic protein folding.

Main Methods:

• Review of established knowledge on bacterial protein export and folding.
• Focus on the periplasmic maltose-binding protein as a model system.

Main Results:

• Proteins destined for the periplasm often utilize N-terminal signal sequences for targeting to the inner membrane.
• Translocation across the inner membrane is followed by signal sequence cleavage, enabling mature protein folding.
• Chaperones, folding catalysts, and proteases are crucial for maintaining quality control during periplasmic protein maturation.

Conclusions:

• The bacterial periplasm employs a complex system involving signal sequences, secretion machinery, and quality control factors for proper protein folding.
• Understanding these principles is vital for comprehending bacterial cell biology and developing targeted interventions.