Elucidation of roles for vitamin B-12 in regulation of folate, ubiquinone, and methionine metabolism

作者：Romine Margaret F; Rodionov Dmitry A; Maezato Yukari; Anderson Lindsey N; Nandhikonda Premchendar; Rodionova Irina A; Carre Alexandre; Li Xiaoqing; Xu Chengdong; Clauss Therese R W; Kim Young Mo; Metz Thomas O; Wright Aaron T

来源：Proceedings of the National Academy of Sciences, 2017, 114(7): E1205-E1214.

DOI：10.1073/pnas.1612360114

• chemical biology
• cobalamin
• metabolism
• microbial regulation

Only a small fraction of vitamin B-12-requiring organisms are able to synthesize B-12 de novo, making it a common commodity in microbial communities. Initially recognized as an enzyme cofactor of a few enzymes, recent studies have revealed additional B-12-binding enzymes and regulatory roles for B-12. Here we report the development and use of a B-12-based chemical probe to identify B-12-binding proteins in a nonphototrophic B-12-producing bacterium. Two unexpected discoveries resulted from this study. First, we identified a light-sensing B-12-binding transcriptional regulator and demonstrated that it controls folate and ubiquinone biosynthesis. Second, our probe captured proteins involved in folate, methionine, and ubiquinone metabolism, suggesting that it may play a role as an allosteric effector of these processes. Thesemetabolic processes produce precursors for synthesis of DNA, RNA, and protein. Thereby, B-12 likely modulates growth, and by limiting its availability to auxotrophs, B-12-producing organisms may facilitate coordination of community metabolism.

• 出版日期2017-2-14