Enterococcus faecalis V583 cell membrane protein expression to alkaline stress.

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Enterococcus faecalis is a resilient bacterium found in failed endodontic treatments.
• Its ability to adapt to extreme alkaline conditions is well-documented.
• The specific role of membrane proteins in this adaptation remains largely unknown.

Purpose of the Study:

• To investigate the role of Enterococcus faecalis membrane proteins in survival under extreme alkaline conditions.
• To identify specific membrane proteins that are differentially regulated at high pH.

Main Methods:

• Enterococcus faecalis V583 was cultured in a chemostat at pH 8 and pH 11.
• Membrane proteins were identified using membrane shaving and isotope-coded protein labeling.
• Quantitative analysis of protein abundance was performed using LC-ESI mass spectrometry and MaxQuant software.

Main Results:

• Six proteins were upregulated at pH 11, including polysaccharide biosynthesis, glycerol uptake facilitator, and glycosyl hydrolase.
• Five proteins were downregulated at pH 11, including C4-dicarboxylate transporter and several PTS system components.
• A shift in carbohydrate metabolism from the PTS system to glycerol uptake was observed.

Conclusions:

• Enterococcus faecalis membrane proteins play a crucial role in adapting to extreme alkaline environments.
• The observed metabolic shift supports the formation of a protective capsule, enhancing cell survival.
• These findings provide insights into the survival mechanisms of E. faecalis in challenging conditions.