IMPRINTING STRUCTURED PEPTIDES: A STEP TOWARD FOLDING ASSISTANCE?
Biological functions in livings arise from macromolecular interactions and ultimately rely on the stereo- and chemical-complementarity between the binding partners. In the case of interacting proteins, it has been shown that particular protein segments, such as exposed loops, turns, helix-loop-helix motifs, etc. are actively involved in the formation of those complexes that trigger the physiological responses.
With the aim to mimic protein interactors and to improve the recognition properties of biomimetics prepared by molecular imprinting technique [1], polyacrylamide molecularly imprinted nanoparticles (nanoMIPs) were synthesized in precipitation polymerization conditions [2], selecting both linear and constrained peptides as templates, in an example based on a linear 9mer peptide C1alk-(X)n=7-C9alk and on its structured homologous, the loop-shaped C1-(X)n=7-C9 closed by a disulphyde bond.
The nanoMIPs were about 50 nm in size and 2 106 Da of mean molecular weight. They exhibited high affinity (Kd = 9 10-9 M) and structural selectivity for the loop-shaped peptide. Additionally, it was observed that the nanoMIPs promoted a fast formation of the loop-shaped peptide, by the oxidation of the linear precursor peptide [3].
These results demonstrated the feasibility of the structural imprinting and hinted at a possible role of the nanoMIPs to assist the refolding of peptide segments into defined structures, anticipating polymeric nanomachines for counteracting folding defects.
References
[1] G. Wulff and A. Sarhan, Angew. Chem. Int. Ed. 11, 341(1972); R. Arshady and K. Mosbach, Die Makromoleculare Chemie, 182, 687 (1981). [2] N. Perez-Moral and A. G. Mayes, Anal. Chim. Acta 504, 15 (2004); Y. Hoshino et al. Journal of American Chemical Society, 130, 15242 (2008). [3] L. Cenci, G. Guella, E. Andreetto, E. Ambrosi, A. Anesi, A.M. Bossi. Nanoscale 8, 15665 (2016).
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