21ff
Cryo-EM structure of DddT in closed substrate-free conformation
Structural highlights
Publication Abstract from PubMedDimethylsulfoniopropionate (DMSP) is a ubiquitous marine organosulfur compound central to microbial stress responses, chemotaxis, and nutrient cycling. Its catabolism produces dimethylsulfide (DMS), a climate-active gas, and plays a key role in the global sulfur cycle. However, the molecular basis of DMSP import, underpinning its microbial metabolism, remains poorly understood. Here, we identify and characterize the BCCT-family transporter DddT from Psychrobacter sp. D2, a marine gamma-proteobacterium that utilizes DMSP as a carbon source. DddT is essential for DMSP uptake and functions as a Na(+)-coupled symporter driven by the transmembrane sodium gradient. Using cryo-electron microscopy, we determined DddT structures in multiple conformational states, revealing its Na(+)-dependent transport mechanism involving two sodium ions, one coordinated by a previously uncharacterized binding site. Sequence analysis shows that DddT-like proteins with conserved sodium-binding features are widespread in marine bacteria, suggesting this Na(+)-coupled transport mechanism represents a broadly conserved feature of the BCCT family. Our findings provide mechanistic insights into sodium-driven substrate uptake and marine sulfur cycling. Structural insights into bacterial dimethylsulfoniopropionate import by BCCT-family transporters.,Zhang YZ, Zhu WJ, Li K, Ding HT, Hattori M, Liu S, Ge C, Qin QL, Teng ZJ, Liu NH, Cao HY, Li CY, Chen XL, Shen QT, Todd JD, Liu LN, Wang P EMBO J. 2026 May 8. doi: 10.1038/s44318-026-00798-w. PMID:42104083[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||
