The styrene monooxygenase system

Area of Science:

• Biochemistry
• Enzyme kinetics
• Biotechnology

Background:

• Styrene monooxygenases (SMO) are flavoproteins catalyzing styrene epoxidation.
• Their two-component structure (SMOB and SMOA) presents unique mechanistic and biotechnological potential.
• Understanding SMO is crucial for applications in green synthesis and bioremediation.

Purpose of the Study:

• To present methods for expressing and characterizing the reductase (SMOB) and epoxidase (SMOA) components of styrene monooxygenase.
• To facilitate independent and composite evaluation of SMO's catalytic system.
• To enable detailed mechanistic studies of flavin reduction, substrate binding, and energy coupling.

Main Methods:

• Expression of SMOB and SMOA components in E. coli using pET-vectors.
• Independent and composite evaluation of flavin reduction and styrene epoxidation reactions.
• Application of steady-state and pre-steady-state kinetic assays.
• Experimental determination of equilibrium-binding reactions and electrochemical midpoint potentials of FAD.

Main Results:

• Successful expression of native and N-terminally histidine-tagged SMO components.
• Established methods for independent analysis of SMOB and SMOA functions.
• Facilitated studies on flavin-ligand binding and energy coupling within the SMO system.
• Demonstrated applicability to wild-type Pseudomonas putida (S12) SMO.

Conclusions:

• The presented approaches enable comprehensive characterization of styrene monooxygenase.
• Independent analysis of SMO components simplifies mechanistic investigations.
• These methods are valuable for studying related two-component enzyme systems.
• The findings support the use of SMO in biotechnological applications.