Table IV

Modified peptides identified from the endoprotease AspN digest

Ion detectedMH+calculatedStructureΔ[ppm]
490.323 (2+)a,b979.5941APEmbedded Image(M3,Ac)APAAAA10+44
483.325 (2+)965.5781APEmbedded Image(M2,Ac)APAAAA10+66
476.315 (2+)951.5631APEmbedded Image(Me,Ac)APAAAA10+62
520.332 (2+)a,b1039.6151APEmbedded Image(M3,Ac)APAATT10+47
507.941 (5+)a,b2535.5241APEmbedded Image(M3,Ac)APAATTEKKVKKAPTTEKK23+59
505.139 (5+)2521.5081APEmbedded Image(M2,Ac)APAATTEKKVKKAPTTEKK23+62
502.335 (5+)2507.4931APEmbedded Image(Me,Ac)APAATTEKKVKKAPTTEKK23+60
495.932 (5+)a,b2475.5031APEmbedded Image(M3,Ac)APAAAAEKKVKKAPTTEKK23+51
493.120 (5+)2461.4871APEmbedded Image(M2, Ac)APAAAAEKKVKKAPTTEKK23+33
490.324 (5+)a,b2447.4721APEmbedded Image(Me,Ac)APAAAAEKKVKKAPTTEKK23+47
563.26 (9+)5061.34[1–45] H2B.1+Me–12
564.82 (9+)5075.38[1–45] H2B.1+M2–12
566.36 (9+)a,c5089.24[1–45]H2B.1+M3–12
567.92 (9+)5103.28[1–45]H2B.1+Ac,Me–12
569.45 (9+)5117.05[1–45]H2B.1+Ac,M2–12
569.90 (9+)5121.10[1–45] H2B.2+Me–12
571.03 (9+)5131.27[1–45] H2B.1+Ac,M3–12
573.03 (9+)a,c,d5149.27[1–45]H2B.2+M3–12
574.56 (9+)5163.04[1–45]H2B.2+Ac,Me–12
576.14 (9+)5177.26[1–45]H2B.2+Ac,M2–12
577.70 (9+)a,c5191.30[1–45]H2B.2+Ac,M3–12
  • a Identity confirmed by CID.

  • b Doubly modified internal fragments establish Lys-3, and -4 as the sites of modification.

  • c In all spectra b5is the first N-terminal fragment detected. No “diagnostic” internal fragments were observed.

  • d Dimethyl derivative also detected overlapping with the Ac,Me3-modified H2B.1 peptide ions.