Selective isolation of N‐terminal peptides from proteins and their de novo sequencing by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry without regard to unblocking or blocking of N‐terminal amino acids
peer-reviewed · Rapid Communications in Mass Spectrometry · 2008
| Date | 2008-10-30 |
| Type | peer-reviewed |
| Venue | Rapid Communications in Mass Spectrometry |
| Publisher | Wiley |
| Contribution | algorithm |
| DOI | 10.1002/rcm.3735 |
| Citations (OpenAlex) | 23 |
| Venue 2-year citedness | 1.80 |
Abstract
We have developed a new method to determine the N-terminal amino acid sequences of proteins, regardless of whether their N-termini are modified. This method consists of the following five steps: (1) reduction, S-alkylation and guanidination for targeted proteins; (2) coupling of sulfo-NHS-SS-biotin to N(alpha)-amino groups of proteins; (3) digestion of the modified proteins by an appropriate protease followed by oxidation with performic acid; (4) specific isolation of N-terminal peptides from digests using DITC resins; (5) de novo sequence analysis of the N-terminal peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) using the CAF (chemically assisted fragmentation) method or tandem mass spectrometric (MS/MS) analysis according to unblocked or blocked peptides, respectively. By employing DITC resins instead of avidin resins used in our previous method (Yamaguchi et al., Rapid Commun. Mass Spectrom. 2007; 21: 3329), it has been possible to isolate selectively N-terminal peptides from proteins regardless of modification of N-terminal amino acids. Here we propose a universal method for N-terminal sequence analysis of proteins.
Methods and tools
- N-terminal peptide isolation with CAF de novo sequencing: Isolates protein N-terminal peptides on DITC resin, whether or not the N-terminus is blocked, then sequences them de novo by MALDI-TOF using chemically assisted fragmentation or MS/MS.