Table II

Homologous contig sequences from the venom dataset

The segments identical to the de novo reconstructions are shown underlined. On the de novo sequences, parentheses indicate sequences where the order of the amino acids was not determined; square brackets indicate indistinguishable amino acid masses (on ion trap spectra). A homologous sequence is confirmed (✓) if it matches the peptides obtained by independent traditional database search of the assembled MS/MS spectra. This confirmation step turned out positive whenever the homologous peptide was present in the database (albeit on a protein from a different snake species); assembled spectra in the remaining homologous contig sequences had no significant match to the database and were thus neither confirmed nor refuted. All C. atrox homologies were either matched to a different snake species or can be explained by single nucleotide polymorphisms of the original sequences, which were also detected in our sample. The complete list of all putative homolog peptides can be found in our supplemental materials as well as annotated MS/MS spectra for all novel homologies.

De novo sequenceHomologous matchedHomologous proteinSpecies, protein name
L(TP)GSQCAD(GV)CCDQCRF[Q,K]LTPGSQCADGVCCDQCRFTO42138✓Agkistrodon contortrix laticinctus, metalloproteinase-disintegrin-like protein
LRPGSQCAEGMCCDQCRFMQ2QA03C. durissus durissus, metalloproteinase P-II
LRPGAQCADGLCCDQCRFIP68520C. atrox, platelet aggregation activation inhibitor
KVLNEDEQTRD(PK) KVLNEDEQTRDPK Q9DF66✓Trimeresurus jerdonii, venom serine proteinase 3
KVPNEDEQTRNPKQ8QHK2C. atrox, serine protease catroxase II
(LTNCSPK)(TD)IYSYSWKR LTNCSPKTDIYSYSWKR Q71QE8Crotalus viridis viridis, phospholipase A2
Y(MF)(YL)DFLCTDPSEKC YMFYLDFLCTDPSEK Q71QE8✓C. viridis viridis, phospholipase A2
IVSWGGDPCAQPREPGVYTKQ71QH8✓T. stejnegeri, serine protease CL4
IVSWGGDICAQPREPEPYTKQ2QA04C. durissus durissus, serine proteinase