title: Label-Free Relative Quantitation of Isobaric and Isomeric Human Histone H2A and H2B Variants by Fourier Transform Ion Cyclotron Resonance Top-Down MS/MS.
abstract: Histone variants are known to play a central role in genome regulation and maintenance. However, many variants are inaccessible by antibody-based methods or bottom-up tandem mass spectrometry due to their highly similar sequences. For many, the only tractable approach is with intact protein top-down tandem mass spectrometry. Here, ultra-high-resolution FT-ICR MS and MS/MS yield quantitative relative abundances of all detected HeLa H2A and H2B isobaric and isomeric variants with a label-free approach. We extend the analysis to identify and relatively quantitate 16 proteoforms from 12 sequence variants of histone H2A and 10 proteoforms of histone H2B from three other cell lines: human embryonic stem cells (WA09), U937, and a prostate cancer cell line LaZ. The top-down MS/MS approach provides a path forward for more extensive elucidation of the biological role of many previously unstudied histone variants and post-translational modifications.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , 95 Chieftain Way, Tallahassee, Florida 32306-4390, United States.
authors.forename: Xibei
authors.initials: X
authors.lastname: Dang
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia , 724 Biological Sciences Building, Athens, Georgia 30602-2607, United States.
authors.forename: Amar
authors.initials: A
authors.lastname: Singh
authors.affiliation: Department of Biological Science, Florida State University , 319 Stadium Drive, Tallahassee, Florida 32306-4295, United States.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Spetman
authors.affiliation: Cell and Molecular Pharmacology & Experimental Therapeutics, Medical University of South Carolina , 173 Ashley Avenue, Charleston, South Carolina 29425, United States.
authors.forename: Krystal D
authors.initials: KD
authors.lastname: Nolan
authors.affiliation: Cell and Molecular Pharmacology & Experimental Therapeutics, Medical University of South Carolina , 173 Ashley Avenue, Charleston, South Carolina 29425, United States.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Isaacs
authors.affiliation: Department of Biological Science, Florida State University , 319 Stadium Drive, Tallahassee, Florida 32306-4295, United States.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Dennis
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia , 724 Biological Sciences Building, Athens, Georgia 30602-2607, United States.
authors.forename: Stephen
authors.initials: S
authors.lastname: Dalton
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , 95 Chieftain Way, Tallahassee, Florida 32306-4390, United States.|Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory , 1800 East Paul Dirac Drive, Tallahassee, Florida 32310-4005, United States.
authors.forename: Alan G
authors.initials: AG
authors.lastname: Marshall
authors.affiliation: Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory , 1800 East Paul Dirac Drive, Tallahassee, Florida 32310-4005, United States.|Verna & Marrs McLean Dept. of Biochemistry & Molecular Biology, Baylor College of Medicine , One Baylor Plaza, Houston, Texas 77030-3411, United States.
authors.forename: Nicolas L
authors.initials: NL
authors.lastname: Young
mesh_terms: D002460:Cell Line; D017357:Cyclotrons; D014644:Genetic Variation; D056914:Genomic Structural Variation; D006657:Histones / Q000032:analysis* / Q000235:genetics; D006801:Humans; D011499:Protein Processing, Post-Translational; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D006657:Histones
keywords: FT-ICR; FTMS; histone; post-translational modification; proteoform; sequence variants