Making Top–Down Sequencing of All/Any Proteins a Reality. How Might This Be Accomplished?
We describe here the current state-of-the-art in doing, what is termed, top-down sequencing (TDS) of proteins and peptides, using modern mass spectrometry (MS) together with novel fragmentation mechanisms (e.g., ECD, ETD, UVPD, CID and others). Though reviews of this topic have appeared in recent years, there are none that purport how to accomplish 100% sequencing effectiveness of TDS-MS for all and any proteins, regardless of size and molecular weights (MWs). Thus, this is not a simple overview of what has already been described in the open literature on TDS-MS. Rather, it suggests how, in the future, it should be possible to realize 100% effectiveness, using thermally unfolded proteins. These must be in their fully open, denatured states, within the mass spectrometer, as a function of keeping them heated to 400-450C, throughout the MS fragmentation process. Thus, this chapter does not yet relate actual, such results but rather, is speculative and suggestive in its intent and nature.