Abstract:

A novel human plasma proteome sample pretreatment strategy was developed based on the interaction of random oligonucleotides with human plasma proteins, such as ionic interaction, affinity interaction, hydrophobic interaction, hydrogen bonding or spatial structure and so on. Random oligonucleotide library was immobilized on the magnetic particles by biotin-avidin interaction, and dispersed in 20 mmol/L Tris-HCl buffer (pH 7.4), followed by incubation with plasma proteins. Two elution systems were used to elute the proteins interacted with random oligonucleotides, separately. Nano-RPLC-ESI-MS/MS analysis was performed for protein identification. The number of proteins identified after treatment was increased by 29.5%, and two elution systems displayed good complementarity (26.7%). The total ratio of spectral counts of the top ten high abundant protein in human plasma was decreased from 31.82% to 21.31% (elution system 1) and 26.20% (elution system 2). In all the proteins identified, the lowest abundant protein (0.29 ng/mL) was only identified after magnetic nanoparticles@single-stranded DNA (MNP@ssDNA) treatment, which demonstrated that this strategy not only decreased the abundance of highly abundant proteins, but also provided a new idea for digging more lowly abundant proteins.

Key words: high abundance, low abundance, plasma, protein, random oligonucleotide library, spectral count