Functional compartmentalization and metabolic separation in a prokaryotic cell

Area of Science:

• Cell Biology
• Microbiology
• Biochemistry

Background:

• Prokaryotic cells traditionally viewed as simple
• bags of enzymes.
• Bacteria possess microcompartments for metabolic enzymes, concentrating them and preventing side reactions.
• Ignicoccus hospitalis, a hyperthermophilic archaeon, has a unique double-membrane structure with an unknown intermembrane compartment function.

Purpose of the Study:

• To investigate the function of the intermembrane compartment in Ignicoccus hospitalis.
• To determine the location of enzymes involved in autotrophic CO2 assimilation.
• To understand the spatiofunctional organization of this archaeon's cellular processes.

Main Methods:

• Immunogold labeling of ultrathin sections.
• Microscopy to visualize enzyme localization.
• Analysis of cellular compartments in Ignicoccus hospitalis.

Main Results:

• Enzymes for autotrophic CO2 assimilation are located in the intermembrane compartment.
• This compartment is now named the peripheric cytoplasmic compartment.
• This compartmentalization is unprecedented in prokaryotes.

Conclusions:

• The peripheric cytoplasmic compartment in I. hospitalis houses carbon metabolism enzymes.
• This organization may protect genetic material (DNA, RNA) from reactive aldehydes.
• Demonstrates a unique example of metabolic and informational process compartmentalization in prokaryotes.