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Title | Structure and mechanism of sulfofructose transaldolase, a key enzyme in sulfoquinovose metabolism. |
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Journal, issue, pages | Structure, Vol. 31, Issue 3, Page 244-252.e4, Year 2023 |
Publish date | Mar 2, 2023 |
Authors | Alexander J D Snow / Mahima Sharma / Palika Abayakoon / Spencer J Williams / James N Blaza / Gideon J Davies / |
PubMed Abstract | Sulfoquinovose (SQ) is a key component of plant sulfolipids (sulfoquinovosyl diacylglycerols) and a major environmental reservoir of biological sulfur. Breakdown of SQ is achieved by bacteria through ...Sulfoquinovose (SQ) is a key component of plant sulfolipids (sulfoquinovosyl diacylglycerols) and a major environmental reservoir of biological sulfur. Breakdown of SQ is achieved by bacteria through the pathways of sulfoglycolysis. The sulfoglycolytic sulfofructose transaldolase (sulfo-SFT) pathway is used by gut-resident firmicutes and soil saprophytes. After isomerization of SQ to sulfofructose (SF), the namesake enzyme catalyzes the transaldol reaction of SF transferring dihydroxyacetone to 3C/4C acceptors to give sulfolactaldehyde and fructose-6-phosphate or sedoheptulose-7-phosphate. We report the 3D cryo-EM structure of SF transaldolase from Bacillus megaterium in apo and ligand bound forms, revealing a decameric structure formed from two pentameric rings of the protomer. We demonstrate a covalent "Schiff base" intermediate formed by reaction of SF with Lys89 within a conserved Asp-Lys-Glu catalytic triad and defined by an Arg-Trp-Arg sulfonate recognition triad. The structural characterization of the signature enzyme of the sulfo-SFT pathway provides key insights into molecular recognition of the sulfonate group of sulfosugars. |
External links | Structure / PubMed:36805128 |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 2.1 - 3.2 Å |
Structure data | EMDB-15960, PDB-8bc2: EMDB-15961, PDB-8bc3: EMDB-15962, PDB-8bc4: PDB-8c4i: |
Chemicals | ChemComp-HOH: ChemComp-QC9: |
Source |
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Keywords | TRANSFERASE / transaldolase / cryo-EM / decamer / sulfofructose / Sulfofugar |