Outer membrane cytochromes/flavin interactions in Shewanella spp.-A molecular perspective

Area of Science:

• Microbiology
• Biochemistry
• Bioenergetics

Background:

• Extracellular electron transfer (EET) is vital for microbial energy metabolism and biotechnological applications.
• Understanding EET mechanisms at the bionano interface is complex, involving intricate molecular interactions.
• Shewanella oneidensis MR-1 is a model organism for studying EET due to its versatile electron transfer pathways.

Purpose of the Study:

• To elucidate the molecular mechanisms of EET in Shewanella oneidensis MR-1.
• To investigate the interfacial interactions between outer-membrane cytochromes (OMCs) and flavins.
• To provide a molecular perspective on how OMCs bind to electron shuttles like riboflavin (RF) and flavin mononucleotide (FMN).

Main Methods:

• Utilized molecular docking simulations to model interactions between OMCs and flavins.
• Analyzed protein-ligand interactions by examining electrostatic potential, hydrophilicity/hydrophobicity, and van der Waals surfaces.
• Focused on the outer-membrane cytochromes OmcA and MtrC and their interactions with RF and FMN.

Main Results:

• Proposed that OMC-flavin interactions are primarily driven by geometrical recognition.
• Identified specific binding sites and orientations for riboflavin (RF) and flavin mononucleotide (FMN) on OmcA and MtrC, respectively.
• Visualized the interfacial relationships and docking poses between OMCs and flavins.

Conclusions:

• Geometrical recognition is a key factor in the binding of flavins to outer-membrane cytochromes in Shewanella oneidensis MR-1.
• The findings provide a molecular basis for understanding electron transfer at the bionano interface.
• This research contributes to the broader understanding of microbial EET and its biotechnological potential.