Identification of a functional dddD ‐ Rh for dimethyl sulfide production in the Antarctic Rhodococcus sp. NJ‐530

• Published in: Journal of Basic Microbiology
• Main Authors: Wang, Wenyu, Qu, Changfeng, Wang, Xixi, Gao, Xuxu, Zhang, Honghai, Miao, Jinlai
• Other Authors: Natural Science Foundation of Shandong Province, China Ocean Mineral Resources Research and Development Association
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2020
• Subjects: Applied Microbiology and Biotechnology; General Medicine; Antarc*; Antarctic; Southern Ocean
• Online Access: http://dx.doi.org/10.1002/jobm.202000032; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjobm.202000032; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jobm.202000032

Abstract Dimethylsulfoniopropionate (DMSP) is widespread in the oceans, and its biological metabolite, dimethyl sulfide (DMS), plays an important role in the atmosphere. The Antarctic region has become a hotspot in DMS studies due to the high spatial and temporal variability in DMS(P) concentration, but the level of bacterial DMS production remains unclear. In this study, a bacterium isolated from Antarctic floating ice, Rhodococcus sp. NJ‐530, was found to metabolize DMSP into DMS, and the rate of DMS production was measured as 3.96 pmol·mg protein −1 ·h −1 . Rhodococcus sp. NJ‐530 had a DddD‐ Rh enzyme containing two CaiB domains, which belonged to the CoA‐transferase III superfamily. However, the DddD‐ Rh had a molecular weight of 73.21 kDa, which was very different from previously characterized DddD enzymes in sequence and evolution. In vitro assays showed that DddD‐ Rh was functional in the presence of acetyl‐CoA. This was the first functional DddD from Gram‐positive Actinobacteria. Moreover, a quantitative real‐time polymerase chain reaction revealed that high temperature facilitated the expression of dddD ‐ Rh , and changes of salinity had little effect on it. This study adds new evidence to the bacterial DMS production in the Southern Ocean and provides a basis for investigating the metabolic mechanism of DMSP in extreme environments.