Isolation of streptococcal hyaluronate synthase.

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• Hyaluronan is a crucial glycosaminoglycan in extracellular matrices.
• Understanding hyaluronan synthesis is vital for various biological and medical applications.
• Streptococci are known producers of hyaluronan, making them a relevant model organism.

Purpose of the Study:

• To isolate and characterize the hyaluronate synthase enzyme from streptococci.
• To confirm the enzyme's molecular weight and its role in hyaluronan biosynthesis.
• To develop methods for purifying and studying the active enzyme.

Main Methods:

• Isolation of hyaluronate synthase from streptococcal protoblast membranes using Triton X-114 extraction and cetylpyridinium chloride precipitation.
• Identification of the enzyme as a 52,000-Mr protein through binding and affinity labeling studies.
• Characterization of enzyme activity using antibodies and analysis of enzyme-deficient mutants.
• Solubilization and purification of the active synthase using cholate and ion-exchange chromatography.

Main Results:

• A 52,000-Mr protein was identified as the hyaluronate synthase.
• The purified enzyme demonstrated binding to nascent hyaluronate and was affinity-labeled by UDP-glucuronic acid and UDP-N-acetylglucosamine.
• Antibodies against the 52,000-Mr protein effectively inhibited hyaluronate synthesis.
• Mutants lacking hyaluronate synthase activity were devoid of the 52,000-Mr protein in membrane extracts.
• The active synthase was successfully solubilized and purified.

Conclusions:

• The 52,000-Mr protein is confirmed as the hyaluronate synthase in streptococci.
• This study provides a method for the purification and characterization of a key enzyme in hyaluronan biosynthesis.
• The findings contribute to a deeper understanding of bacterial glycosaminoglycan synthesis.