biostudies-literatureXin YMOST | National Key Research and Development Program of China (NKPs)MOST | National Key Research and Development Program of ChinaMOST | National Natural Science Foundation of China (NSFC)MOST | National Natural Science Foundation of Chinae0192624https://www.ebi.ac.uk/biostudies/studies/S-EPMC11921322biostudies-literatureUnknown91(3)Polysulfides commonly occur in anaerobic, microbial active environments, where they play key roles in sulfur cycling and redox transformations. Anaerobic survival of microorganisms requires the formation of protein disulfide bond (DSB). The relationship between polysulfides and anaerobic DSB formation has not been studied so far. Herein, we discovered that polysulfides can efficiently mediate protein DSB formation of microorganisms under anaerobic conditions. We used polysulfides to treat proteins, including roGFP2, Trx1, and DsbA, under anaerobic conditions and found that all three proteins formed intramolecular DSB <i>in vitro</i>. Under anaerobic conditions, <i>Escherichia coli</i> Δ<i>dsbB</i> displayed reduced growth and decreased intracellular protein DSB levels, but polysulfide treaApplied and environmental microbiologyPolysulfides promote protein disulfide bond formation in microorganisms growing under anaerobic conditions.PMC119213222022YFC340130192351302Xia YLiu HYang JXun LWang QXin YWu XfalsePolysulfides promote protein disulfide bond formation in microorganisms growing under anaerobic conditions.Polysulfides commonly occur in anaerobic, microbial active environments, where they play key roles in sulfur cycling and redox transformations. Anaerobic survival of microorganisms requires the formation of protein disulfide bond (DSB). The relationship between polysulfides and anaerobic DSB formation has not been studied so far. Herein, we discovered that polysulfides can efficiently mediate protein DSB formation of microorganisms under anaerobic conditions. We used polysulfides to treat proteins, including roGFP2, Trx1, and DsbA, under anaerobic conditions and found that all three proteins formed intramolecular DSB <i>in vitro</i>. Under anaerobic conditions, <i>Escherichia coli</i> Δ<i>dsbB</i> displayed reduced growth and decreased intracellular protein DSB levels, but polysulfide trea2025-01-01T00:00:00Z2025 Mar2026-06-02T07:17:36.489Z2025-04-05T12:38:17.003ZS-EPMC119213223991831810.1128/aem.01926-24