Cytoplasmic sulfur trafficking in sulfur-oxidizing prokaryotes

Area of Science:

• Biochemistry
• Microbiology
• Biotechnology

Background:

• Persulfide groups are chemically versatile, participating in numerous biochemical pathways.
• Protein-bound persulfides supply sulfane sulfur for biosynthetic pathways.
• Less recognized roles exist in enzymatic sulfur generation, transfer, and oxidation during dissimilatory sulfur oxidation.

Purpose of the Study:

• To review current information on sulfur trafficking in sulfur-oxidizing prokaryotes.
• To discuss the central role of protein-bound sulfur in preventing free sulfide.
• To highlight the significance of sulfur trafficking and TusA homologous proteins in these pathways.

Main Methods:

• Literature review of existing scientific information on sulfur trafficking.
• Analysis of biochemical pathways involved in sulfur oxidation in prokaryotes.
• Discussion of the proposed model for sulfur presentation to oxidizing enzymes.

Main Results:

• Sulfur trafficking, including persulfide generation and transfer, is essential for dissimilatory sulfur oxidation.
• Sulfur is consistently presented to cytoplasmic oxidizing enzymes in a protein-bound form.
• TusA homologous proteins are identified as central and common elements in these sulfur trafficking processes.

Conclusions:

• Sulfur trafficking is a fundamental process in sulfur-oxidizing prokaryotes.
• Protein-bound sulfur prevents the accumulation of toxic free sulfide within prokaryotic cells.
• TusA proteins play a critical role in mediating essential sulfur trafficking pathways.