Single molecule de novo protein sequencing based on the 'superspecificity' of amino-acyl tRNA synthetases (aaRS) is proposed. An unfolded protein molecule is threaded through a nanopore in an electrolytic cell (e-cell) to expose the terminal residue in the e-cell's trans chamber. After the residue is cleaved with an exopeptidase, a set of tRNAs, their aaRSs, and ATP are added to trans. An aaRS charges a cognate tRNA molecule with the residue. The charged tRNA (along with the other reactants) is transferred to an extended e-cell with N (20 ≤ N ≤ 61) pores in N individual cis chambers and a single trans chamber. Each pore holds an RNA molecule ending in a unique codon that is exposed in trans. The charged tRNA's anticodon base-pairs with the terminal codon of an RNA. If tRNAs and residues are fluorescently tagged with two different colors, the residue can be identified from the observed position of the resulting color pair. As charging is 'superspecific' identification is unambiguous. The protein molecule in the first e-cell is advanced by one residue and the process repeated. In this approach there is no need for precise pore current or optical intensity measurements. Potential implementation issues are discussed. Other possibilities, including one in which the terminal residue is cleaved after charging, are also examined.
Keywords:
Subject: Biology and Life Sciences - Biochemistry and Molecular Biology
Copyright: This open access article is published under a Creative Commons CC BY 4.0 license, which permit the free download, distribution, and reuse, provided that the author and preprint are cited in any reuse.
Preprints.org is a free preprint server supported by MDPI in Basel, Switzerland.