Optimizing Archaeal Lipid Biosynthesis in Escherichia coli

Area of Science:

• Biochemistry
• Evolutionary Biology
• Microbiology

Background:

• Archaea possess distinct membrane lipid chemistry from bacteria and eukaryotes, known as the lipid divide.
• Early membrane evolution may have involved mixed lipid stages, with instability potentially driving the lipid divide.
• Previous attempts to co-express archaeal and bacterial lipids in E. coli yielded limited success.

Purpose of the Study:

• To engineer E. coli for substantial production of archaeal lipids.
• To investigate the compatibility and formation of mixed archaeal/bacterial membrane lipids.
• To explore the evolutionary implications of the lipid divide by creating novel lipid compositions.

Main Methods:

• Overexpression of archaeal phosphatidylserine synthase to enhance archaeal lipid production.
• Introduction of a synthetic isoprenoid utilization pathway to increase precursor supply.
• Analysis of lipid composition and growth characteristics of engineered E. coli.

Main Results:

• Significantly increased production of archaeal lipid archaetidylethanolamine in E. coli.
• Formation of novel hybrid archaeal/bacterial cardiolipin species.
• Engineered E. coli exhibited enhanced sensitivity to cerulenin, indicating dependence on native phospholipids.

Conclusions:

• Metabolic engineering can successfully increase archaeal lipid production in E. coli.
• Mixed archaeal and bacterial membrane lipids can be synthesized, forming novel hybrid species.
• The study provides insights into the lipid divide and the stability of early biological membranes.