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Publication Abstract from PubMed

2(S)-dihydroxypropanesulfonate (DHPS) is a microbial degradation product of 6-deoxy-6-sulfo-d-glucopyranose (sulfoquinovose), a component of plant sulfolipid with an estimated annual production of 10(10) tons. DHPS is also at millimolar levels in highly abundant marine phytoplankton. Its degradation and sulfur recycling by microbes, thus, play important roles in the biogeochemical sulfur cycle. However, DHPS degradative pathways in the anaerobic biosphere are not well understood. Here, we report the discovery and characterization of two O2-sensitive glycyl radical enzymes that use distinct mechanisms for DHPS degradation. DHPS-sulfolyase (HpsG) in sulfate- and sulfite-reducing bacteria catalyzes C-S cleavage to release sulfite for use as a terminal electron acceptor in respiration, producing H2S. DHPS-dehydratase (HpfG), in fermenting bacteria, catalyzes C-O cleavage to generate 3-sulfopropionaldehyde, subsequently reduced by the NADH-dependent sulfopropionaldehyde reductase (HpfD). Both enzymes are present in bacteria from diverse environments including human gut, suggesting the contribution of enzymatic radical chemistry to sulfur flux in various anaerobic niches.

Two radical-dependent mechanisms for anaerobic degradation of the globally abundant organosulfur compound dihydroxypropanesulfonate.,Liu J, Wei Y, Lin L, Teng L, Yin J, Lu Q, Chen J, Zheng Y, Li Y, Xu R, Zhai W, Liu Y, Liu Y, Cao P, Ang EL, Zhao H, Yuchi Z, Zhang Y Proc Natl Acad Sci U S A. 2020 Jun 22. pii: 2003434117. doi:, 10.1073/pnas.2003434117. PMID:32571930^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.