Polypeptide Requirement of Multicomponent Monooxygenase DsoABCDEF for Dimethyl Sulfide Oxidizing Activity

Area of Science:

• Microbiology
• Biochemistry
• Enzymology

Background:

• The multicomponent monooxygenase DsoABCDEF from Acinetobacter sp. strain 20B catalyzes dimethyl sulfide (DMS) oxidation to dimethyl sulfoxide (DMSO).
• DsoABCDEF shares sequence similarity with other known multicomponent monooxygenases, such as MopKLMNOP and DmpKLMNOP.

Purpose of the Study:

• To elucidate the specific subunit requirements for DMS-oxidizing activity within the DsoABCDEF system.
• To investigate the functional compatibility of Dso subunits with homologous Dmp polypeptides.

Main Methods:

• Polypeptide requirement experiments were conducted to determine the essential components for DMS oxidation.
• Heterologous complementation assays were performed using deletion mutants and corresponding Dmp polypeptides.

Main Results:

• DMS-oxidizing activity was dependent on DsoB, C, D, E, and F, with DsoA being non-essential.
• Complementation of DsoC and DsoF deletion mutants with Dmp polypeptides retained DMS-oxidizing activity.
• Complementation of DsoB, DsoD, or DsoE deletion mutants with Dmp polypeptides significantly reduced or abolished activity.

Conclusions:

• The DsoABCDEF system exhibits specific subunit requirements for DMS oxidation.
• DsoC and DsoF demonstrate functional complementation with their Dmp counterparts, suggesting conserved roles.
• The oxygenase subunits (DsoB, D, E) are less tolerant to heterologous complementation, indicating crucial subunit-specific interactions.