Fragmentation of Peptide -Radical Cations

Fragmentation of Peptide -Radical Cations

Julia Laskin, Zhibo Yang, C. M. Dominic Ngand Ivan K. Chu

Supporting information

Figure S1. LTQ/Orbitrap MS3 spectrum of a) the M+ ion of FRWGKPVGY and MS4 spectra of -radical cations produced by the loss of b) C-terminal CO2,c) C4H9N (71) of lysine, d) C7H6O (106) of tyrosine, and e) C4H9N3(99) of arginine. Fragment ions shifted by the mass of the corresponding side chain are marked with apostrophes.

Table S1. Complete assignment of MS/MS ion trap spectra shown in Figure 2.

Experimental m/z / Normalized Abundance / Calculated m/z / Peak
Assignment
MS/MS spectrum of the [GVYIHPF]+ ion
382.1 / 6.5
400.1 / 10.2 / 400.2 / y3
432.1 / 8.2 / 432.2 / b4-H
497.1 / 10.8 / 497.3 / z4
541.0 / 10.2 / 541.3 / a5-H
569.1 / 100.0 / 569.3 / b5-H
660.1 / 9.8 / 660.3 / z5
676.1 / 43.3 / 676.3 / y5
775.2 / 12.9 / 775.4 / y6
831.3 / 45.7 / 831.4 / M
MS/MS spectrum of the [GVYIHPF]+ ion
384.1 / 4.3 / 384.2 / z3
400.1 / 8.6 / 400.2 / y3
432.0 / 8.2 / 432.2 / b4-H
468.1 / 5.2 / 468.2 / wa4
497.1 / 24.1 / 497.3 / z4
513.1 / 3.7 / 513.3 / y4
542.1 / 21.7 / 542.3 / a5
569.1 / 100.0 / 569.3 / b5-H
639.2 / 7.7 / 639.4 / a6
660.0 / 9.4 / 660.3 / z5
676.2 / 40.0 / 676.3 / y5
703.0 / 5.2 / 703.3 / x5+H
725.2 / 92.1 / 725.4 / M-106
759.1 / 3.7 / 759.4 / z6
775.3 / 20.2 / 775.4 / y6
786.3 / 37.6 / 786.4 / M-COOH
802.2 / 16.1 / 802.4 / M-29
813.2 / 9.0 / 813.4 / M-H2O
831.3 / 31.9 / 831.4 / M
MS/MS spectrum of the [GVYIHPR]+ ion
201.2 / 6.7 / 201.1 / x1
243.8 / 44.8
270.8 / 48.3 / 271.2 / y2-H
298.9 / 98.7 / 299.2 / x2+H
336.2 / 15.8 / 336.2 / c3-H
393.1 / 88.0 / 393.2 / z3
436.0 / 11.3 / 435.2 / x3+H
464.2 / 12.2 / 464.2 / v4
477.2 / 26.8 / 477.3 / wa4
493.0 / 19.8
506.1 / 49.9 / 506.3 / z4
542.2 / 15.5 / 542.3 / a5
577.2 / 24.6 / 577.3 / v5
613.2 / 14.0
669.1 / 52.2 / 669.4 / z5
683.2 / 14.8 / 683.4 / c6-H
712.2 / 11.5 / 711.4 / x5+H
734.2 / 50.3 / 734.2 / M-106
741.2 / 22.8 / 740.4 / M-99 (R )
743.2 / 12.4
754.3 / 24.6 / 754.3 / M-86 (R )
768.1 / 10.4 / 768.4 / z6
784.3 / 100.0 / 784.3 / y6
805.4 / 25.7 / 805.3 / M-NH3-H2O
811.3 / 62.5 / 811.4 / M – 29 (I)
822.2 / 39.7 / 822.4 / M-H2O
823.3 / 12.3 / 823.4 / M-NH3
825.3 / 46.4 / 825.4 / M-NH2
840.3 / 69.0 / 840.5 / M

Table S2. Complete assignment of LTQ/Orbitrap MS/MS spectra of RPKPQQFYGLM-NH2 shown in Figure 3.

Experimental m/z / Normalized Abundance / Calculated m/z / Peak
Assignment
MS/MS spectrum of the M+ ion
854.4995 / 29.3 / 854.4995 / a7
982.4814 / 6.7 / 982.4815 / y8
1017.5629 / 27.2 / 1017.5629 / a8
1094.5581 / 4.7 / 1094.5577 / z9
1205.6137 / 15.5 / 1205.6136 / y10-2H
1206.6217 / 4.6 / 1206.6214 / y10-H
1207.6295 / 39.3 / 1207.6292 / y10
1214.6319 / 4.9 / 1214.6316 / M-87(R )-61(M)
1217.6103 / 7.6 / 1217.6136 / M-58(Q)-87(R )
1220.6121 / 3.1 / 1220.6119 / M-71(K)-71(Q)
1230.6741 / 4.1 / 1230.6742 / M-58(Q)-74(M)
1232.6409 / 3.9 / 1232.6409 / M-56(L)-74(M)
1233.6202 / 3.3 / 1233.6197 / M-58(Q)-71(K )
1256.6808 / 4.7 / 1256.6807 / M-106(Y)
1263.6430 / 26.6 / 1263.6428 / M-99(R )
1275.6433 / 8.2 / 1275.6428 / M-87(R )
1276.6508 / 80.0 / 1276.6507 / M-86 (R )
1288.7038 / 13.7 / 1288.7035 / M-74(M)
1291.6494 / 39.9 / 1291.6490 / M-71(K)
1301.7113 / 48.5 / 1301.7113 / M-61(M)
1304.6930 / 100.0 / 1304.6932 / M-58(Q)
1306.6602 / 5.6 / 1306.6599 / M-56(L)
1315.7270 / 4.5 / 1315.7269 / M-47(M)
1319.6673 / 19.2 / 1319.6677 / M-43(L)
1346.7037 / 7.3 / 1346.7038 / M-NH2
1362.7225 / 73.8 / 1362.7225 / Mdot
MS/MS spectrum of the M+-56 (L) ion
854.4994 / 25.7 / 854.4995 / a7
926.4198 / 5.3 / 926.4189 / y8-56
1017.5626 / 23.4 / 1017.5629 / a8
1149.5517 / 8.4 / 1149.5510 / y10-2H-56
1151.5660 / 24.1 / 1151.5666 / y10-56
1174.6132 / 3.6 / 1174.6116 / M-56-58(Q)-74(M)
1207.5801 / 20.2 / 1207.5802 / M-56-99(R )
1219.5801 / 6.5 / 1219.5802 / M-56-87(R )
1220.5876 / 45.7 / 1220.5881 / M-56-86 (R )
1232.6401 / 20.1 / 1232.6409 / M-56-74(M)
1235.5863 / 40.3 / 1235.5864 / M-56-71(K)
1235.6193 / 15.3 / 1235.6228 / M-56-71(Q)
1245.6485 / 38.7 / 1245.6487 / M-56-61(M)
1248.6305 / 100.0 / 1248.6306 / M-56-58(Q)
1259.6644 / 5.9 / 1259.6643 / M-56-47(M)
1290.6428 / 4.2 / 1290.6412 / M-56-NH2
1306.6597 / 51.8 / 1306.6599 / M-56(L)
MS/MS spectrum of the M+-71(K) ion
783.4257 / 47.1 / 783.4260 / a7-71(K)
946.4891 / 51.2 / 946.4894 / a8-71
982.4811 / 6.0 / 982.4815 / y8
1039.5023 / 4.8 / 1039.5030 / y9-71
1136.5555 / 28.9 / 1136.5557 / y10-71
1146.5931 / 8.8 / 1146.5929 / M-71-74(M)-71(Q)
1177.5567 / 4.9 / 1177.5571 / M-71-58(Q)-56(L)
1185.6067 / 8.7 / 1185.6072 / M-71-106(Y)
1192.5698 / 3.2 / 1192.5693 / M-71-99(R )
1217.6300 / 31.5 / 1217.6300 / M-71-74(M)
1220.6117 / 32.3 / 1220.6119 / M-71-71(Q)
1230.6379 / 59.5 / 1230.6378 / M-71-61(M)
1233.6196 / 100.0 / 1233.6197 / M-71-58(Q)
1235.5866 / 12.0 / 1235.5864 / M-71-56(L)
1244.6532 / 7.8 / 1244.6534 / M-71-47(M)
1248.5940 / 32.6 / 1248.5942 / M-71-43(L)
1275.6297 / 4.5 / 1275.6303 / M-71-NH2
1291.6490 / 80.2 / 1291.6490 / M-71(K)
MS/MS spectrum of the M+-74(M) ion
854.4992 / 34.8 / 854.4995 / a7
908.4621 / 5.4 / 908.4625 / y8-74
1017.5624 / 26.2 / 1017.5629 / a8
1020.5389 / 6.3 / 1020.5387 / z9-74
1131.5942 / 12.4 / 1131.5945 / y10-2H-743
1132.6017 / 4.9 / 1132.6024 / y10-H-74
1133.6100 / 40.1 / 1133.6102 / y10-74
1143.5946 / 7.7 / 1143.5945 / M-74-58(Q)-87(R )
1146.5931 / 5.3 / 1146.5929 / M-74-71(K)-71(Q)
1159.5991 / 3.5 / 1159.6007 / M-74-58(Q)-71(K )
1160.5974 / 3.6 / 1160.5973 / x10+H-74
1161.5671 / 6.7 / 1161.5674 / M-74-56(L)-71(K)
1161.6045 / 5.1 / 1161.6037 / M-74-56(L)-71(Q)
1174.6116 / 4.9 / 1174.6116 / M-74-58(Q)-56(L)
1182.6615 / 5.3 / 1182.6617 / M-74-106(Y)
1189.6232 / 26.0 / 1189.6238 / M-74-99(R )
1201.6241 / 7.6 / 1201.6238 / M-74-87(R )
1202.6312 / 69.1 / 1202.6316 / M-74-86 (R )
1217.6298 / 44.4 / 1217.6300 / M-74-71(K)
1217.6648 / 21.2 / 1217.6663 / M-74-71(Q)
1230.6737 / 100.0 / 1230.6742 / M-74-58(Q)
1232.6404 / 22.7 / 1232.6409 / M-74-56(L)
1245.6477 / 23.4 / 1245.6487 / M-74-43(L)
1272.6843 / 5.2 / 1272.6847 / M-74-NH2
1288.7026 / 6.2 / 1288.7035 / M-74(M)
MS/MS spectrum of the M+-99(R) ion
755.4196 / 28.2 / 755.4199 / a7-99
792.4039 / 10.0 / 792.4039 / KPQQFY
817.3874 / 4.2 / 817.3879 / PQQFYGL-NH3
834.4140 / 14.9 / 834.4145 / PQQFYGL
889.4565 / 9.8 / 889.4567 / PKPQQFY
918.4829 / 37.8 / 918.4833 / a8-99
947.4446 / 4.9 / 947.4444 / y8-NH3-H2O
948.4285 / 6.2 / 948.4285 / y8-2NH3
962.5093 / 32.2 / 962.5094 / KPQQFYGL
965.4546 / 38.4 / 965.4550 / y8-NH3
982.4812 / 98.5 / 982.4815 / y8
1059.5620 / 11.8 / 1059.5622 / PKPQQFYGL
1093.5497 / 56.7 / 1093.5499 / y9-NH3
1110.5766 / 50.7 / 1110.5765 / y9
1115.5757 / 8.7 / 1115.5758 / b10-H-99
1118.5856 / 4.8 / 1118.5867 / M-99-74(M)-71(Q)
1131.5940 / 10.4 / 1131.5945 / M-99-58(Q)-74(M)
1133.5607 / 8.9 / 1133.5612 / M-99-56(L)-74(M)
1134.5391 / 6.2 / 1134.5401 / M-99-58(Q)-71(K )
1149.5492 / 4.4 / 1149.5510 / M-99-58(Q)-56(L)
1157.6013 / 9.6 / 1157.6010 / M-99-106
1185.6049 / 12.9 / 1185.6051 / M-99-NH3-61(M)
1188.5864 / 4.9 / 1188.5870 / M-99-NH3-58(Q)
1189.6236 / 19.9 / 1189.6238 / M-99-74(M)
1190.6026 / 26.3 / 1190.6027 / y10-NH3
1192.5698 / 9.8 / 1192.5693 / M-99-71(K)
1192.6053 / 19.5 / 1192.6057 / M-99-71(Q)
1202.6308 / 61.2 / 1202.6316 / M-99-61(M)
1205.6133 / 100.0 / 1205.6136 / M-99-58(Q)
1207.5791 / 6.2 / 1207.5802 / M-99-56(L)
1207.6292 / 55.3 / 1207.6292 / y10
1216.6463 / 5.9 / 1216.6473 / M-99-47(M)
1220.5878 / 29.1 / 1220.5881 / M-99-43(L)
1244.6236 / 5.5 / 1244.6245 / M-99-H2O-H
1245.6318 / 5.3 / 1245.6323 / M-99-H2O
1246.6158 / 28.5 / 1246.6163 / M-99-NH3
1263.6425 / 84.8 / 1263.6428 / M-99(R )
MS/MS spectrum of the M+-106(Y) ion
854.4990 / 30.0 / 854.4995 / a7
876.4407 / 4.1 / 876.4397 / y8-106
1099.5724 / 8.5 / 1099.5718 / y10-2H-106
1101.5871 / 34.8 / 1101.5874 / y10-106
1108.5880 / 3.1 / 1108.5898 / M-106-87(R )-61(M)
1111.5707 / 4.6 / 1111.5718 / M-106-58(Q)-87(R )
1114.5711 / 3.1 / 1114.5701 / M-106-71(K)-71(Q)
1124.6330 / 5.1 / 1124.6324 / M-106-58(Q)-74(M)
1126.5979 / 3.6 / 1126.5991 / M-106-56(L)-74(M)
1127.5780 / 3.2 / 1127.5779 / M-106-58(Q)-71(K )
1157.6007 / 24.2 / 1157.6010 / M-106-99(R )
1169.6010 / 6.0 / 1169.6010 / M-106-87(R )
1170.6086 / 52.6 / 1170.6089 / M-106-86 (R )
1182.6613 / 17.0 / 1182.6617 / M-106-74(M)
1185.6072 / 53.7 / 1185.6072 / M-106-71(K)
1185.6435 / 15.4 / 1185.6436 / M-106-71(Q)
1195.6694 / 52.2 / 1195.6695 / M-106-61(M)
1198.6511 / 100.0 / 1198.6514 / M-106-58(Q)
1200.6170 / 5.6 / 1200.6181 / M-106-56(L)
1209.6842 / 6.3 / 1209.6851 / M-106-47(M)
1213.6244 / 19.9 / 1213.6259 / M-106-43(L)
1240.6618 / 5.8 / 1240.6620 / M-106-NH2
1256.6799 / 26.0 / 1256.6807 / M-106(Y)