Sequence Scrambling in Collision-Induced Dissociation of Y-Type Fragment Ions

Supporting Information

Sequence Scrambling in Collision-Induced Dissociation of y-Type Fragment Ions

Mahsan Miladi, Brett Harper, and Touradj Solouki

Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76798

Figure S1. Collision-induced dissociation (CID) mass spectra of the m/z-isolated (a) [y6]+ (m/z 511) (generated from CID of doubly charged AAAAHAA-NH2) and (b) [y6 – (NH3)]+ (m/z494) (generated from CID of [y6]+) at 20 % normalized collision energy. Insets in panels (a) and (b) show the expanded views of m/zrange of 422.1 to 422.3 corresponding to identified sequence scrambledfragment ion(i.e.,[y6 – (NH3 + A)]+) with mass measurementerrors of 4.2 and 0.5 ppm, respectively.

Figure S2. Collision-induced dissociation (CID) mass spectra of the m/z-isolated (a) [y5]+ (m/z440) (generated from CID of doubly charged AAAAHAA-NH2) and (b) [y5 – (NH3)]+ (m/z423) (generated from CID of [y6]+) at 20 % normalized collision energy. Insets in panels (a) and (b) show the expanded views of m/zrange of 351.0to 351.3 corresponding to identified sequence scrambled fragment ion (i.e., [y5 – (NH3 + A)]+) with mass measurement errors ~ 3.3 and 0.1 ppm respectively.

Figure S3. Collision-induced dissociation (CID) mass spectra of the m/z-isolated (a) [y4]+ (m/z 440) (generated from CID of doubly charged AAAAHAA-NH2) and (b) [y4 – (NH3)]+ (m/z423) (generated from CID of [y4]+) at 20 % normalized collision energy. Insets in panels (a) and (b) show the expanded views of m/zrange of 351.0 to 351.3 corresponding to identified sequence scrambled fragment ion (i.e., [y4 – (NH3 + A)]+) with mass measurement accuracy of 0.5 and 0.4 ppm respectively.

Table S1.The fragment ion identity, theoretically calculatedm/z values, experimentally observedm/z values, and error (ppm) of the assigned fragment ions observed in CID mass spectrum of [y7]+2(FRWGKPV-NH2) from des-acetylated--melanocyte. The sequence-scrambled fragment ions are shown in boldface.

Table S2.The fragment ion identity, theoretically calculated m/z values, experimentally observed m/z values, and error (ppm)of the assigned fragment ions observed in CID mass spectrum of [y7 – (NH3)]+2 from des-acetylated--melanocyte. The sequence-scrambled fragment ion is shown in boldface.

Table S3.The fragment ion identity, theoretically calculated m/z values, experimentally observed m/z values, and error (ppm) of the assigned fragment ions observed in CID mass spectrum of [y7]+ [GVYVHPV]fromangiotensin II. The sequence-scrambled fragment ions are shown inboldface.

Table S4.Fragment identity, theoretically calculated m/z values, experimentally observed m/z values, and error (ppm) of assigned fragment ions observed in CID spectrum of [y7–(H2O + PV)]+ fromangiotensin II. The fragment ions that could be assigned as scrambled ions are shown in boldface.

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