On January 27, Prof. Zhang Yuzhong's team from OUC’s College of Marine Life Sciences and Frontier Science Center of Deep Ocean Multispheres and Earth System published a paper entitled ‘Ubiquitous occurrence of a dimethylsulfoniopropionate ABC transporter in abundant marine bacteria’ online in The ISME Journal.
Dimethylsulfoniopropionate (DMSP), an important carrier for the global carbon and sulfur cycles, is an organic sulfur compound prevalent in the marine environment, which plays an important role in marine microbiology. Bacteria SAR11 and marine roseobacter group (MRG) are the two most widespread bacterial groups in surface seawater, efficiently absorbing nanomolar quantities of DMSP from seawater and accumulating DMSP concentrations to the millimolar level. However, it is not clear how the SAR11 and MRG groups of bacteria take up DMSP from seawater into the cell.
This study employed an integrated approach of comparative genomics, genetics and biochemistry. A specific transporter system, DmpXWV, is identified from Ruegeria pomeroyi DSS-3, a representative strain of bacteria from the MRG taxon. Its physiological and genetic analyses indicate that this transporter system is significant for DMSP uptake by strain DSS-3.
By means of structural and biochemical analyses, the study reveals the molecular mechanism by which DmpX recognizes and binds DMSP. It shows that the DmpX protein is widely distributed in many marine bacteria, through a bioinformatics analysis, including SAR11 and MRG. In addition, the dmpX gene is transcribed at a high level in the global ocean, suggesting that many marine bacteria can use this transport system to efficiently enrich DMSP in seawater. This study contributes to the understanding of the process that drives the organic sulfur cycle in marine bacteria and its adaptation to the environment.
