| Autor: |
Kaur A; School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia., Pickles IB; York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, U.K., Sharma M; York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, U.K., Madeido Soler N; ACRF Chemical Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3010, Australia.; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia., Scott NE; Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria 3000, Australia., Pidot SJ; Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria 3000, Australia., Goddard-Borger ED; ACRF Chemical Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3010, Australia.; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia., Davies GJ; York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, U.K., Williams SJ; School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia. |
| Abstrakt: |
The sulfosugar sulfoquinovose (SQ) is produced by photosynthetic plants, algae, and cyanobacteria on a scale of 10 billion tons per annum. Its degradation, which is essential to allow cycling of its constituent carbon and sulfur, involves specialized glycosidases termed sulfoquinovosidases (SQases), which release SQ from sulfolipid glycoconjugates, so SQ can enter catabolism pathways. However, many SQ catabolic gene clusters lack a gene encoding a classical SQase. Here, we report the discovery of a new family of SQases that use an atypical oxidoreductive mechanism involving NAD + as a catalytic cofactor. Three-dimensional X-ray structures of complexes with SQ and NAD + provide insight into the catalytic mechanism, which involves transient oxidation at C3. Bioinformatic survey reveals this new family of NAD + -dependent SQases occurs within sulfoglycolytic and sulfolytic gene clusters that lack classical SQases and is distributed widely including within Roseobacter clade bacteria, suggesting an important contribution to marine sulfur cycling. |
