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Dimethylsulfoniopropionate lyase DddK and related proteins, cupin domain This family includes mostly bacterial proteins homologous to dimethylsulfoniopropionate lyase DddK from marine bacterium Pelagibacter. DddK cleaves dimethylsulfoniopropionate (DMSP), the organic osmolyte and antioxidant produced in marine environments, and yields acrylate and the climate-active gas dimethyl sulfide (DMS). DddK contains a double-stranded beta-helical motif which utilizes various divalent metal ions as cofactors for catalytic activity; however, nickel, an abundant metal ion in marine environments, confers the highest DMSP lyase activity. Also included in this family is Plu4264, a Photorhabdus luminescens manganese-containing cupin shown to have similar metal binding site to TM1287 decarboxylase, but two very different substrate binding pockets. The Plu4264 binding pocket shows a cavity and substrate entry point more than twice as large as and more hydrophobic than TM1287, suggesting that Plu4264 accepts a substrate that is significantly larger than that of TM1287, a putative oxalate decarboxylase. Thus, the function of Plu4264 could be similar to that of TM1287 but with a larger, less charged substrate. Proteins in this family belong to the cupin superfamily with a conserved "jelly roll-like" beta-barrel fold. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",