Table 3.

Mascot search result scores of digested proteome extracts from three different ostrich bone specimens analysed months apart and the similarity to the ostrich (Struthio) sequence as a percentage. Note that the first tryptic peptide of the emboldened sequence was also matched in every sample without the missed cleavage at the K residue. Underlined residues indicate post-translational modification (oxidation of P/K; deamidation of N); scores in parentheses represent higher scores with deamidated peptides or with one additional oxidation. m/z, mass-to-charge ratio.

peptide sequencem/zCC1254CC507UM902similarity (%)
BrachyA1/TrexA1GVQGPPGPQGPR1161.65753 (60)59 (65)100
BrachyA1GPSGPQGPSGAPGPK1305.6717453 (80)100
BrachyA1/TrexA1GSAGPPGATGFPGAAGR1458.794120123100
BrachyA1GETGPAGPAGPPGPAGAR1531.7848566100
BrachyA1GLTGPIGPPGPAGAPGDK1589.8587545100
BrachyA1GLTGPIGPPGPAGAPGDKGEAGPSGPPGPTGAR2878.4454536 (44a)100
BrachyA2/TrexA2GLPGESGAVGPAGPPGSRb1577.870767889
BrachyA2GSNGEPGSAGPPGPAGLR1608.780 (93)58 (79)71100
BrachyA1/TrexA1GATGAPGIAGAPGFPGAR1571.8747358100
TrexA1GAPGPQGPSGAPGPK1305.6696246 (71)100
TrexA1GVVGLPGQR897.5504650100
  • aScore with one additional oxidation.

  • bPeptide was considered unique to T. rex but see electronic supplementary material, S1–S6.