Nucleoporins are a category of protein that forms pores within the nuclear envelope, regulating transport of biomolecules into and out of the nucleus with remarkable selectivity and permeability. This combination makes the nuclear pore an attractive model for bioseparations and an interesting subject for biophysical study. As a result, many nucleoporins have been cloned and studied in detail, yielding gels that can replicate many of the selective separation properties of the natural system. Building on this, we show that a consensus repeat of 19 amino acids can be extracted from one of the most widely studied nucleoporins, Nsp1. When this repeat sequence is polymerized, it forms a nucleoporin-like protein (NLP) that can mimic the properties of the natural protein with a dramatically simplified amino acid sequence. This sequence provides the ability to selectively transport proteins and to selectively enrich and transport proteins down to the 1-10 nM level. A series of different mutations to the base sequence have been explored to provide detailed information on how sequence design regulates transport.<br/><br/>Inspired by these results from engineered NLPs, modelling was used to better understand the function of the system with the hope of capturing its function in synthetic polymer biomaterials. Using concepts of associative polymer diffusion, a hypothesis was put forward to explain the function of these simplified NLPs based on the presence of walking and hopping diffusive modes in the gels. This hypothesis suggests design rules which allow the same transport properties observed in NLPs to be replicated in peptide-functionalized poly(ethylene glycol) (PEG) gels, completing the design cycle of adapting the performance of a natural material to a fully synthetic system based on insight into its fundamental transport mechanism. This shows great potential for advances in protein separation technology, including antibodies and protein toxins.

Nucleoporin-like proteins and bioinspired gels

2019 Fall National Meeting

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