Use of Deuterium-Labeled Lysine for Efficient Protein Identification and Peptide de Novo Sequencing

peer-reviewed · Analytical Chemistry · 2002

peer-reviewed · Analytical Chemistry · 2002. Sheng Gu et al. Here, we describe a method for protein identification and de novo peptide sequencing. Through in vivo cell…
Date 2002-11-01
Type peer-reviewed
Venue Analytical Chemistry
Publisher American Chemical Society (ACS)
Contribution algorithm
DOI 10.1021/ac0204350
Citations (OpenAlex) 42
Venue 2-year citedness 7.10

Abstract

Here, we describe a method for protein identification and de novo peptide sequencing. Through in vivo cell culturing, the deuterium-labeled lysine residue (Lys-d4) introduces a 4-Da mass tag at the carboxyl terminus of proteolytic peptides when cleaved by certain proteases. The 4-Da mass difference between the unlabeled and the deuterated lysine assigns a mass signature to all lysine-containing peptides in any pool of proteolytic peptides for protein identification directly through peptide mass mapping. Furthermore, it was used to distinguish between N- and C-terminal fragments for accurate assignments of daughter ions in tandem MS/MS spectra for sequence assignment. This technique simplifies the labeling scheme and the interpretation of the MS/MS spectra by assigning different series of fragment ions correctly and easily and is very useful in de novo peptide sequencing. We have also successfully implemented this approach to the analysis of protein mixtures derived from the human proteome.

Authors

  1. Sheng Gu · Los Alamos National Laboratory, University of California, Davis
  2. Songqin Pan · Los Alamos National Laboratory, University of California, Davis
  3. E. Morton Bradbury · Los Alamos National Laboratory, University of California, Davis
  4. Xian Chen · Los Alamos National Laboratory, University of California, Davis

Methods and tools

  • Amino acid-coded mass tagging: Codes amino acids by mass before MALDI TOF/TOF so that incomplete CID of singly and doubly charged precursors still yields assignable series, recovering spectra that would otherwise go unidentified and making the instrument’s throughput usable for de novo work.

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