Skip to main content
. 2016 Mar 2;7(15):20669–20679. doi: 10.18632/oncotarget.7838

Figure 3. Covalent modification of full-length STAT3 by S3I-201 as analyzed by LC-MS/MS.

Figure 3

Top upper trace provides the fragment ion analysis of the peptide sequence 532LLGPGVNYSGCQITWAK548 for the determination of the alkylation of Cys542. Top lower trace provides the fragment ion analysis of the peptide sequence 686YCRPESQEHPEADPGSAAPYLK707 for the determination of the alkylation of Cys687. Bottom upper trace provides the fragment ion analysis of the peptide sequence 247QQIACIGGPPNICLDR262 for the determination of the alkylation of Cys259. Bottom lower trace provides the fragment ion analysis of the peptide sequence 366VCIDKDSGDVAALR379 for the determination of the alkylation of Cys367. The central image was generated on PyMol image software using PDB: 4E68 where modified Cys residues are highlighted in red. Cys108, also shown alkylated by S3I-201 is unresolved in PDB code 4E68 and is thus excluded from the figure above. The LC-MS/MS analysis for Cys108 is found in the Supplementary Figure S2 and extensive list of identified MS/MS fragment ions found in Supplementary Tables S6, S7, S8, S9, and S10.