Multiple dimensions of unique molecular structure information can now be obtained from proteins and DNA using mass spectrometry. Less than 10-6 mol of the active major histocompatibility complex signaling peptide in a mixture of thousands can be identified. For large proteins (>40 kDa), the high resolving power (>105) and 10-17 mol sensitivity of Fourier-transform mass spectrometry provide exact molecular weight values (± 1 or 2 Da) for mixture components, indicating errors or modifications compared with the predicted DNA sequence. Selecting a specific molecular species, its two-dimensional spectrum indicates the part of the molecule that is modified; a three-dimensional spectrum of that fragment further isolates the modification site.
ASJC Scopus subject areas
- Analytical Chemistry