Open AccessDirect mass spectrometric analysis of intact proteins of the yeast large ribosomal subunit using capillary LC/FTICR
Author(s) -
Sang Won Lee,
Scott J. Berger,
Suzana Martinović,
Ljiljana PašaTolić,
Gordon A. Anderson,
Yufeng Shen,
Rui Zhao,
Richard Smith
Publication year - 2002
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.082119899
Subject(s) - ribosomal protein , top down proteomics , electrospray ionization , mass spectrometry , protein subunit , fourier transform ion cyclotron resonance , chemistry , ribosome , biochemistry , ribosomal rna , protein mass spectrometry , chromatography , rna , gene
Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry coupled with capillary reverse-phase liquid chromatography was used to characterize intact proteins from the large subunit of the yeast ribosome. High mass measurement accuracy, achieved by "mass locking" with an internal standard from a dual electrospray ionization source, allowed identification of ribosomal proteins. Analyses of the intact proteins revealed information on cotranslational and posttranslational modifications of the ribosomal proteins that included loss of the initiating methionine, acetylation, methylation, and proteolytic maturation. High-resolution separations permitted differentiation of protein isoforms having high structural similarity as well as proteins from their modified forms, facilitating unequivocal assignments. The study identified 42 of the 43 core large ribosomal subunit proteins and 58 (of 64 possible) core large subunit protein isoforms having unique masses in a single analysis. These results demonstrate the basis for the high-throughput analyses of complex mixtures of intact proteins, which we believe will be an important complement to other approaches for defining protein modifications and their changes resulting from physiological processes or environmental perturbations.