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. Author manuscript; available in PMC: 2017 Sep 15.
Published in final edited form as: Chembiochem. 2016 Sep 7;17(18):1738–1751. doi: 10.1002/cbic.201600266

Figure 13.

Figure 13

Evaluation of TFSeM (as 7b) incorporation into GB1 by ESI-MS. While TFSeM incorporation was not observed, SeM’s presence was detected even though it was not included in the defined growth media. (A) Deconvoluted mass spectrum showing GB1 Val39Met grown with a 9:1 ratio of SeM:Met in RF11. The expected and observed molecular weight for GB1 Val39Met with Met is 6181 Da and with SeM is 6228 Da (observed 6229 Da). (B) Mass spectrum showing GB1 Val39Met grown with a 9:1 ratio of TFSeM:Met in RF11. The expected molecular weight GB1 Val39Met with TFSeM is 6282 Da (not observed). (C) Deconvoluted mass spectrum showing GB1 Leu5Met grown with a 9:1 ratio of SeM:Met in RF11. The expected and observed molecular weight for GB1 Leu5Met with Met is 6167 Da and with SeM is 6214 Da. (D) Deconvoluted mass spectrum showing GB1 Leu5Met grown with a 9:1 ratio of TFSeM:Met in RF11. The expected molecular weight GB1 Leu5Met with TFSeM is 6268 Da (not observed).