TY - JOUR
T1 - Differentiation between peptides containing acetylated or tri-methylated lysines by mass spectrometry
T2 - An application for determining lysine 9 acetylation and methylation of histone H3
AU - Zhang, Kangling
AU - Yau, Peter M.
AU - Chandrasekhar, Bhaskar
AU - New, Ron
AU - Kondrat, Richard
AU - Imai, Brian S.
AU - Bradbury, Morton E.
PY - 2004/1
Y1 - 2004/1
N2 - Histone acetylation and methylation play a critical role in transcription and gene regulation. Identification of sites of lysine acetylation and methylation in histones or other proteins by mass spectrometry (MS) is of increasing interest. In this paper, we report the use of MS to differentiate between peptides containing acetylated or tri-methylated lysines. High accuracy matrix-assisted laser desorption/ionization-time of flight MS gives better than five parts per million measurement accuracy, which is sufficient to verify acetylation and/or methylation. Electrospray ionization tandem mass spectrometry was used to assign modification sites and to differentiate acetylation from methylation. Typically, an immonium ion at m/z 98 corresponds to a mono-methylated lysine and an immonium ion at m/z 126 corresponds to an acetylated lysine. The neutral loss ion (MH+-59) is unique for a tri-methylated lysine. For a peptide with two or more modification sites of acetylation or tri-methylation or one site containing partial acetylation and tri-methylation, the a2-, b2-type ion is the characteristic index for an acetylated lysine whereas the b2-59 ion is indicative of a tri-methylated lysine in the N-terminus. The y-type ions and y-59 ions are charateristic of an acetylated lysine and a tri-methylated lysine at the C-terminus, respectively. We demonstrated that a lysine in a peptide modified by methylation or acetylation can be differentiated by MS using our method. Even if more then one lysine is present in a peptide and different modifications of this amino acid occur, they can be distinguished. This method was successful for the determination of the acetylation and methylation status of lysine 9 of histone H3 in chicken erythrocytes and human HeLa cell lines.
AB - Histone acetylation and methylation play a critical role in transcription and gene regulation. Identification of sites of lysine acetylation and methylation in histones or other proteins by mass spectrometry (MS) is of increasing interest. In this paper, we report the use of MS to differentiate between peptides containing acetylated or tri-methylated lysines. High accuracy matrix-assisted laser desorption/ionization-time of flight MS gives better than five parts per million measurement accuracy, which is sufficient to verify acetylation and/or methylation. Electrospray ionization tandem mass spectrometry was used to assign modification sites and to differentiate acetylation from methylation. Typically, an immonium ion at m/z 98 corresponds to a mono-methylated lysine and an immonium ion at m/z 126 corresponds to an acetylated lysine. The neutral loss ion (MH+-59) is unique for a tri-methylated lysine. For a peptide with two or more modification sites of acetylation or tri-methylation or one site containing partial acetylation and tri-methylation, the a2-, b2-type ion is the characteristic index for an acetylated lysine whereas the b2-59 ion is indicative of a tri-methylated lysine in the N-terminus. The y-type ions and y-59 ions are charateristic of an acetylated lysine and a tri-methylated lysine at the C-terminus, respectively. We demonstrated that a lysine in a peptide modified by methylation or acetylation can be differentiated by MS using our method. Even if more then one lysine is present in a peptide and different modifications of this amino acid occur, they can be distinguished. This method was successful for the determination of the acetylation and methylation status of lysine 9 of histone H3 in chicken erythrocytes and human HeLa cell lines.
KW - Histone acetylation
KW - Histone methylation
KW - Histones
KW - Mass spectrometry
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U2 - 10.1002/pmic.200300503
DO - 10.1002/pmic.200300503
M3 - Article
C2 - 14730666
AN - SCOPUS:0942276237
SN - 1615-9853
VL - 4
SP - 1
EP - 10
JO - Proteomics
JF - Proteomics
IS - 1
ER -