The Enteric Bacterium Enterococcus faecalis Elongates and Incorporates Exogenous Short and Medium Chain Fatty Acids...

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Enterococcus faecalis utilizes fatty acids for membrane synthesis.
• De novo fatty acid synthesis is energy-intensive.
• Dietary fatty acids can potentially supplement membrane synthesis.

Purpose of the Study:

• To investigate the mechanism of exogenous fatty acid elongation in E. faecalis.
• To determine the role of specific enzymes and proteins in this process.
• To assess the potential for conserving energy and carbon through fatty acid elongation.

Main Methods:

• Analysis of fatty acid activation and elongation pathways.
• Genetic manipulation (overexpression) of key enzymes like FakAB, AcpA, and PlsX.
• Growth studies using auxotrophic E. faecalis strains.
• Comparative analysis using E. faecalis and Lactococcus lactis PlsX.

Main Results:

• E. faecalis activates and elongates exogenous short- and medium-chain fatty acids via the FakAB system and acyl-ACP intermediates.
• Overexpression of AcpA or PlsX significantly enhances exogenous short-chain fatty acid incorporation.
• Lactococcus lactis PlsX is more efficient than E. faecalis PlsX for short-chain fatty acid elongation.
• Elongated fatty acids are incorporated into phospholipids by PlsY and PlsC, supporting growth of auxotrophic strains.

Conclusions:

• E. faecalis possesses a functional pathway for elongating exogenous fatty acids for phospholipid synthesis.
• This elongation process conserves energy and carbon by reducing de novo synthesis demands.
• Manipulating components of this pathway, like AcpA and PlsX, can enhance fatty acid utilization.