TY - JOUR
T1 - N-terminal protein characterization by mass spectrometry after cyanogen bromide cleavage using combined microscale liquid- and solid-phase derivatization
AU - Nika, Heinz
AU - Hawke, David H.
AU - Angeletti, Ruth Hogue
PY - 2014
Y1 - 2014
N2 - A sample preparation method for protein N-terminal peptide isolation from cyanogen bromide (CNBr) protein digests has been developed. In this strategy, the CNBr cleavage was preceded by protein α- and ε-amine acetylation and carboxyamidomethylation in a one-pot reaction scheme. The peptide mixture was adsorbed on ZipTipC18 pipette tips for reaction of the newly generated N-termini with sulfosuccinimidyl-2- (biotinamido) ethyl-1, 3-dithiopropionate. In the subsequent steps, the peptides were exposed in situ to hydroxylamine for reversal of potential hydroxyl group acylation, followed by reductive release of the disulfide-linked biotinamido moiety from the derivatives. The selectively thiol group-functionalized internal and C-terminal peptides were reversibly captured by covalent chromatography on activated thiol-sepharose, leaving the N-terminal fragment in the flow-through fraction. The use of the reversed-phase support as a venue for postcleavage serial modification proved instrumental to ensure throughput and completeness of derivatization. By this sequence of solid-phase reactions, the N-terminal peptide could be recognized uniquely in the MALDI-mass spectra of unfractionated digests by its unaltered mass signature. The use of the sample preparation method was demonstrated with low-picomole amounts of model protein. The N-terminal CNBr fragments were retrieved selectively from the affinity support. The sample preparation method provides for robustness and simplicity of operation using standard equipment available in most biological laboratories and is anticipated to be readily expanded to gel-separated proteins.
AB - A sample preparation method for protein N-terminal peptide isolation from cyanogen bromide (CNBr) protein digests has been developed. In this strategy, the CNBr cleavage was preceded by protein α- and ε-amine acetylation and carboxyamidomethylation in a one-pot reaction scheme. The peptide mixture was adsorbed on ZipTipC18 pipette tips for reaction of the newly generated N-termini with sulfosuccinimidyl-2- (biotinamido) ethyl-1, 3-dithiopropionate. In the subsequent steps, the peptides were exposed in situ to hydroxylamine for reversal of potential hydroxyl group acylation, followed by reductive release of the disulfide-linked biotinamido moiety from the derivatives. The selectively thiol group-functionalized internal and C-terminal peptides were reversibly captured by covalent chromatography on activated thiol-sepharose, leaving the N-terminal fragment in the flow-through fraction. The use of the reversed-phase support as a venue for postcleavage serial modification proved instrumental to ensure throughput and completeness of derivatization. By this sequence of solid-phase reactions, the N-terminal peptide could be recognized uniquely in the MALDI-mass spectra of unfractionated digests by its unaltered mass signature. The use of the sample preparation method was demonstrated with low-picomole amounts of model protein. The N-terminal CNBr fragments were retrieved selectively from the affinity support. The sample preparation method provides for robustness and simplicity of operation using standard equipment available in most biological laboratories and is anticipated to be readily expanded to gel-separated proteins.
KW - Covalent chromatography
KW - N-terminal peptide
KW - Peptide identification
KW - Reversed-phase supports
UR - http://www.scopus.com/inward/record.url?scp=84897424359&partnerID=8YFLogxK
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U2 - 10.7171/jbt.14-2501-003
DO - 10.7171/jbt.14-2501-003
M3 - Article
C2 - 24688320
AN - SCOPUS:84897424359
SN - 1524-0215
VL - 25
SP - 19
EP - 30
JO - Journal of Biomolecular Techniques
JF - Journal of Biomolecular Techniques
IS - 1
ER -