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Self-assembled proteins are privileged building blocks for the bottom-up organization of matter at the nanoscale. However, since most proteins are very large, they have to be produced by recombinant expression, which is less versatile and flexible than chemical synthesis. Here, we show that we can bridge the potential of proteins for nanofabrication with the simplicity and versatility of solid-phase peptide synthesis by relying on the self-assembly of the viral protein gp23.1, a small 50-residue protein that oligomerizes in solution to form a stable toroidal hexamer. We report the chemical synthesis and basic biophysical characterization of a gp23.1 mutant and show that its self-assembled hexamer templates the formation of highly monodisperse luminescent gold nanoclusters of about 1.3 nm inside its central cavity. This work demonstrates the versatility of this small self-assembled ring protein for a variety of nanotechnological applications.

Combining coordination chemistry and peptide engineering offers extraordinary opportunities for developing novel molecular (supra)structures. Here, we demonstrate that the β-annulus motif is capable of directing the stereoselective assembly of designed peptides containing 2,2′-bipyridine ligands into parallel three-stranded chiral peptide helicates, and that these helicates selectively bind with high affinity to three-way DNA junctions., Financial support from the Spanish grant RTI2018-099877-B-I00, the Xunta de Galicia (Centro singular de Investigación de Galicia accreditation 2016–2019, ED431G/09, and ED431B 2018/04), and the European Union (European Regional Development Fund - ERDF) is gratefully acknowledged. J.G.-G. thanks the Spanish MINECO for his FPI fellowship. D.B. thanks the CIQUS for his 2018 PhD fellowship. G.S. and J.-D.M. thank Spanish MINECO (grant CTQ2017-87889-P) and Generalitat de Catalunya (2017SGR1323) for the financial support. Finally, we would like to thank Prof. Kazunori Matsuura at Tottori University for his valuable input during the preparation of this manuscript.

Self-assembled proteins are privileged building blocks for the bottom-up organization of matter at the nanoscale. However, since most proteins are very large, they have to be produced by recombinant expression, which is less versatile and flexible than chemical synthesis. Here, we show that we can bridge the potential of proteins for nanofabrication with the simplicity and versatility of solid-phase peptide synthesis by relying on the self-assembly of the viral protein gp23.1, a small 50-residue protein that oligomerizes in solution to form a stable toroidal hexamer. We report the chemical synthesis and basic biophysical characterization of a gp23.1 mutant and show that its self-assembled hexamer templates the formation of highly monodisperse gold nanoclusters of about 1.3 nm inside its central cavity. The resulting nanoclusters show catalytic activity in cycloisomerization reactions as well as luminescence emission. This work demonstrates the versatility of this small self- assembled ring protein for a variety of nanotechnological applications.

This is the peer reviewed version of the following article: Boga, S., Bouzada, D., Garcia Pena, D., Vazquez Lopez, M. and Vazquez, M. E. (2018), Sequence‐Specific DNA Recognition with Designed Peptides. Eur. J. Org. Chem., 2018: 249-261, which has been published in final form at https://doi.org/10.1002/ejoc.201700988. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions

A set of Ru(II) metallopeptides containing the dppz ligand has been synthesized using SPPS methods. Fluorescence titration studies show that those metallopeptides featuring an octaarginine tail display a large binding preference for DNA G-quadruplex structures over those lacking it, and also that the interplay between the octoarginine functionalization and the ancillary ligand in the complex has an essential role in the recognition process. Furthermore, the oligoarginine metallopeptides are also efficiently internalized, causing cell death with signs of apoptosis Financial support from the Spanish grants CTQ2015-70698-R, BFU2013-43513-R and SAF2014-56763-R, the Xunta de Galicia Centro Singular de Investigacion de Galicia accreditation 2016–2019.CICECO – Aveiro Institute of Materials, POCI-01-0145-FEDER007679 (UID/CTM/50011/2013), the UE ERDF and the Fundación AECC (IDEAS197VAZQ-Singulares 2014), are acknowledged SI

We describe a lanthanide biosensor that responds to CDK4 kinase activity in melanoma cell extracts through a significant and dose dependent increase in luminescence, thanks to sensitization of a DOTA[Tb3+] complex incorporated into a CDK4 substrate peptide by a unique tryptophan residue in an adjacent phosphoaminoacid binding moiety This work was funded by the CNRS (Centre National de la Recherche Scientifique) and a Marie-Curie fellowship EC-FP7 Framework (PIEF-GA-2013-623151) supporting JAGV. CB was funded by the INCA (PRTK-2014). Financial support from the Spanish MINECO (CTQ2015-70698-R), the Xunta de Galicia (Centro singular de investigacio´n de Galicia accreditation 2016–2019), and the European Union (European Regional Development Fund – ERDF), are gratefully acknowledged SI