Table 1.
Mature peptides detected by LC-MS/MS analysis of native and reduced/alkylated venom samples. Masses shown are monoisotopic.
| Amino Acid Sequence | Precursor | Putative Fold | No. Cys | Theoretical Native Mass (Da) | Observed Native Mass (Da) | Theoretical RAa Mass (Da) | Observed RA Mass (Da) |
|---|---|---|---|---|---|---|---|
| DEKDCIARGQKCVGENKPCCKGTTCMYYANRCVGV | U-RDTX b-Pr1a | ICK c | 6 | 3835.69 | 3835.62 | 4105.89 | 4105.81 |
| TIEKSCKPGTTFKHKDGCNTCKCSDDGKNALCTSKLCL | U-RDTX-Pr11a.2 | Pacifastin | 6 | 4070.88 | 4070.81 | 4341.09 | 4340.99 |
| TMKQSCKPGATFKHKDGCNTCKCSDDGKSARCTARLCW | U-RDTX-Pr10a.2 | Pacifastin | 6 | 4158.86 | 4158.78 | 4429.06 | 4428.96 |
| EEHGCIPPFQPCEGVNSRCCGLYVCFNKICLATP | U-RDTX-Pr2a | ICK | 6 | 3763.65 b | 3763.59 d | 4033.86 d | 4033.77 b |
| SRACSKPGQTVLAPDGCNHCRCSEKGILMACTKMMCPPR | U-RDTX-Pr11a.1 | Pacifastin | 6 | 4172.89 | 4172.82 | 4443.10 | 4442.99 |
| HGCIPPFQPCEGVNSRCCGLYVCFNKICLATP | U-RDTX-Pr2b | ICK | 6 | 3505.57 b | 3505.51 d | 3775.77 d | 3775.68 b |
| GGCIQRYGKCSTENSNCCAPSECYFSFNQCF | U-RDTX-Pr7a | ICK | 6 | 3439.33 | 3439.26 | 3709.53 | 3709.43 |
| CIPAANPCRGNAKCCGNYVCKNGRCLPRS | U-RDTX-Pr5a | ICK | 6 | 3061.39 | 3061.31 | 3331.59 | 3331.52 |
| MMPVCFEGEKLNKDQTKCIKA | U-RDTX-Pr9a | Unknown | 2 | 2410.16 | 2410.13 | 2500.23 | 2500.19 |
| GEDVCIPSGQKCGPYMNMGCCKGLVCMSYAARCVSMGGIPR | U-RDTX-Pr4a | ICK | 6 | 4264.84 | 4264.77 | 4535.05 | 4534.09 |
| MDCKPGKKFKIDCNTCICSKEGKAAACTQKLCLK | U-RDTX-Pr21.2 | Pacifastin | 6 | 3699.79 | 3699.72 | 3970.00 | - |
| CRPGALTVAPDGCNMCTCLSNGKLGRCTHDLICPPR | U-RDTX-Pr12a.1 | Pacifastin | 6 | 3765.73 | - | 4035.93 | 4035.85 |
Cysteine residues inferred by measured masses to form intrachain disulfide bonds are shown highlighted in grey. a RA, reduced and alkylated with 2-iodoethanol (addition of 45.034 Da per half-cystine). b RDTX, reduvitoxin. c ICK, inhibitor cystine knot. d Observed MS1 and MS2 spectra for Pr2a and Pr2b suggest that K28 of Pr2a (K26 of Pr2b) is carbamylated, but this assignation is putative.