Preserving the Sequence of a Biopolymer’s Monomers as They Enter an Electrospray Mass Spectrometer

Reliable, simple, inexpensive methods for sequencing proteins, RNA, or DNA are of obvious interest across biology and medicine. The authors theoretically investigate the conditions under which the monomers of a biopolymer will retain their sequential order against the randomizing effects of Brownian motion, after being cleaved from the polymer while approaching the tip of an electrospray ion source. Their analysis confirms the feasibility of identifying a single protein molecule by delivering its amino acids in order to a mass spectrometer, with 95% likelihood of measuring the correct sequence.