Real-Time Observation of Enzymatic Polyhydroxyalkanoate Polymerization Using High-Speed Scanning Atomic Force...

Area of Science:

• Biochemistry
• Polymer Science
• Microscopy

Background:

• Polyhydroxyalkanoates (PHAs) are biodegradable polymers with diverse applications.
• Understanding the enzymatic polymerization process is crucial for optimizing PHA production.
• Ralstonia eutropha PHA synthase (PhaCRe) is a key enzyme in PHA biosynthesis.

Purpose of the Study:

• To observe the initial in vitro polymerization of PHA by PhaCRe on a mica substrate.
• To investigate the real-time adsorption-desorption dynamics of PhaCRe.
• To elucidate the early stages of PHA chain formation and structure.

Main Methods:

• High-speed scanning atomic force microscopy (HS-AFM) was employed for real-time observation.
• Polymerization was conducted in vitro on a mica substrate in an aqueous environment.
• The adsorption-desorption of PhaCRe and subsequent polymerization were monitored.

Main Results:

• The adsorption-desorption cycle of PhaCRe on mica was observed prior to polymerization.
• PhaCRe transformed into an active enzyme upon contact with PHA monomers within 30 seconds.
• Linearly elongating, rod-shaped objects, larger than single PHA chains, were observed, suggesting semiregular structures.

Conclusions:

• HS-AFM provides real-time insights into enzymatic polymerization processes.
• PhaCRe requires monomer contact for activation and subsequent polymerization.
• The observed PHA structures suggest the formation of organized, possibly semiregular, polymer chains.