TABLE 3.
Fragment ions and fragment loss in the MS/MS spectra of the sperm toxin of B. cereus 4810/72
| Fragment ion m/z (no.) | Fragment lossa |
m/zb
|
||
|---|---|---|---|---|
| Obsvd | Calcd | Δ | ||
| 1125.84 (1) | CO | 28.01 | 27.99 | 0.02 |
| 1082.84 (2) | Ala | 71.01 | 71.04 | −0.03 |
| 1054.84 (3) | Val | 99.01 | 99.07 | −0.06 |
| CO-Ala | 99.01 | 99.03 | −0.02 | |
| 1026.84 (4) | CO-Val | 127.01 | 127.06 | −0.05 |
| 1011.63 (5) | CO-OLeu | 142.22 | 142.06 | 0.16 |
| 968.83 (6) | OLeu-Ala | 185.02 | 185.11 | −0.09 |
| 954.63 (7) | OVal-Val | 199.22 | 199.12 | 0.10 |
| CO-Ala-OVal | 199.22 | 199.08 | 0.14 | |
| 940.83 (8) | Val-OLeu | 213.02 | 213.14 | −0.12 |
| CO-OLeu-Ala | 213.02 | 213.10 | −0.08 | |
| 926.63 (9) | CO-OVal-Val | 227.22 | 227.11 | 0.11 |
| 883.62 (10) | Ala-OVal-Val | 270.23 | 270.16 | 0.07 |
| 869.42 (11) | Val-OLeu-Ala | 284.43 | 284.17 | 0.26 |
| 855.62 (12) | CO-Ala-OVal-Val | 298.23 | 298.15 | 0.08 |
| 841.62 (13) | CO-Val-OLeu-Ala | 312.23 | 312.16 | 0.07 |
| 769.42 (14) | Val-OLeu-Ala-OVal, OLeu-Ala-OVal-Val, Ala-OVal-Val-OLeu, and OVal-Val-OLeu-Ala | 384.43 | 384.24 | 0.19 |
| 741.42 (15) | CO-Val-OLeu-Ala-OVal, CO-OLeu-Ala-OVal-Val, CO-Ala-OVal-Val-OLeu, and CO-OVal-Val-OLeu-Ala | 412.43 | 412.23 | 0.20 |
| 698.42 (16) | Ala-OVal-Val-OLeu-Ala | 455.43 | 455.28 | 0.15 |
| 670.42 (17) | Val-OLeu-Ala-OVal-Val | 483.43 | 483.31 | 0.12 |
| 584.22 (18) | OLeu-Ala-OVal-Val-OLeu-Ala | 569.63 | 569.35 | 0.28 |
| 570.42 (19) | OVal-Val-OLeu-Ala-OVal-Val | 583.43 | 583.36 | 0.07 |
| 556.22 (20) | Val-OLeu-Ala-OVal-Val-Oleu | 597.63 | 597.38 | 0.25 |
| 542.22 (21) | CO-OVal-Val-OLeu-Ala-OVal-Val | 611.63 | 611.37 | 0.26 |
| 499.22 (22) | Ala-OVal-Val-Oleu-Ala-OVal-Val | 654.63 | 654.38 | 0.25 |
| 485.42 (23) | Val-OLeu-Ala-OVal-Val-OLeu-Ala | 668.43 | 668.39 | 0.04 |
| 471.42 (24) | CO-Val-OVal-Ala-OLeu-Val-OVal-Ala | 682.43 | 682.37 | 0.06 |
| 385.22 (25) | (-Val-OLeu-Ala-OVal-)2, (-OLeu-Ala-OVal-Val-)2, (-Ala-OVal-Val-OLeu-)2, and (-OVal-Val-OLeu-Ala-)2 | 768.63 | 768.45 | 0.18 |
| 357.22 (26) | CO(-Val-OLeu-Ala-OVal-)2, CO(-OLeu-Ala-OVal-Val-)2, CO(-Ala-OVal-Val-OLeu-)2, and CO(-OVal-Val-OLeu-Ala-)2 | 796.63 | 796.44 | 0.19 |
| 314.03 (27) | Ala(-OVal-Val-OLeu-Ala-)2 and (-Ala-OVal-Val-OLeu)2 Ala | 839.82 | 839.49 | 0.33 |
| 286.03 (28) | (-Val-OLeu-Ala-OVal-)2Val, Val(-OLeu-Ala-OVal-Val-)2, | 867.82 | 867.51 | 0.31 |
| CO-Ala(-OVal-Val-OLeu-Ala-)2, and CO(-Ala-OVal-Val-OLeu-)2 Ala | 867.82 | 867.48 | 0.34 | |
| 186.03 (29) | (-OVal-Val-OLeu-Ala-)2 OVal-Val | 967.82 | 967.56 | 0.26 |
| 172.03 (30) | (-Val-OLeu-Ala-OVal-)2 Val-OLeu | 981.82 | 981.58 | 0.24 |
Val, Ala, OLeu, and OVal are residues of valine, alanine, 2-hydroxyisocaproic acid, and 2-hydroxyisovaleric acid, respectively. The calculated monoisotopic masses (m/z) are 99.07 (Val), 71.04 (Ala), 114.07 (OLeu), 100.05 (OVal), and 27.99 (CO [carbon monoxide]). The fragment ions in the table represent mass values of MS/MS spectra obtained from the precursor ion, m/z of 1153.85. Fragment loss is precursor ion minus fragment ion. The peptide sequence of fragment loss was assigned by using the known structure [(-OLeu-Ala-OVal-Val)3] of cereulide.
Obsvd, observed; Calcd, calculated; Δ, difference between observed fragment loss and calculated monoisotopic mass.