Characterization of calcifiable proteolipid from Streptococcus mutans

Area of Science:

• Microbiology
• Biochemistry
• Biomineralization

Background:

• Proteolipids are known to initiate calcification in vitro.
• Streptococcus mutans (S. mutans) is a calcifiable bacterium.
• Understanding the composition of S. mutans proteolipids is crucial for explaining its calcifiability.

Purpose of the Study:

• To characterize the apoprotein and phospholipid components of proteolipids from calcifiable S. mutans specimens.
• To elucidate the relationship between proteolipid composition and S. mutans calcifiability.

Main Methods:

• Isolation and characterization of proteolipids from S. mutans.
• Analysis of apoprotein amino acid composition.
• Identification and quantification of phospholipid components.

Main Results:

• Apoproteins contained 16 amino acids with calculated percent polarities ranging from 32.0 to 45.2.
• Acidic phospholipids identified include cardiolipin, mono- and diphosphoinositides, and phosphatidylserine.
• Neutral lipids, phosphatidylethanolamine and phosphatidylcholine, were the most abundant phospholipids.

Conclusions:

• The presence of appropriate hydrophobic proteins and acidic phospholipids in proteolipids accounts for S. mutans calcifiability.
• These findings provide insight into the molecular mechanisms underlying bacterial calcification.