The chirality of helical polypeptides is correlated to that of their constituent amino acid residues. For polypeptides with non-natural backbones, however, such correlations are less clear. Here, circular double helices with torus knot/link topologies were assembled from non-natural metal-peptide chains composed of Ag(I) ions and ditopic tripeptides with Gly-Gly-Ala and Gly-Ala-Gly sequences. We found that the chirality of the assembled helical structures is determined by the l-Ala's dihedral angles. A tubular dimeric structure with an ML composition was further achieved via additional metal cross-linking, showing rational design potential for artificial peptide helices.
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http://dx.doi.org/10.1021/jacs.5c01458 | DOI Listing |
ACS Nano
March 2025
School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen), Shenzhen, Guangdong 518172, P.R. China.
Circularly polarized luminescence (CPL) systems exhibiting room-temperature phosphorescence (RTP) are attracting considerable attention for applications in information encryption and smart sensing. However, achieving ultralong circularly polarized RTP (CPRTP) with tunable chirality and stimuli-responsive CPL remains challenging. Inspired by the color-changing properties of the butterfly, we developed a cellulose nanocrystal (CNC)-based photonic crystal film with an ultralong RTP lifetime of 2.
View Article and Find Full Text PDFProteins
March 2025
School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, Odisha, India.
ZraS is a metal sensor integral to ZraPSR, a two-component signaling system found in enterobacters. It belongs to a family of bifunctional sensor histidine kinases (SHKs) and is speculated to sense zinc-induced stress on the bacterial envelope. Information on the structure-function relationship of sensor kinases is elusive due to the lack of full-length structures, intrinsically dynamic behavior, and difficulty trapping them in active state conformations.
View Article and Find Full Text PDFJ Microbio Robot
March 2025
Department of Physics, Indian Institute Of Science, Bangalore, 560012 Karnataka India.
Unlabelled: Cells are building blocks of living systems. Spatio-temporal mapping of local biophysical changes within cells can lead to novel insights into various biological events. As demonstrated in previous works, successful internalization, controlled manipulation, bio-compatibility, and surface-functionalization capabilities make the helical magnetic nanobots, an ideal candidate for local intracellular measurements.
View Article and Find Full Text PDFJ Am Chem Soc
March 2025
Laboratory for Chemistry and Life Science, Institute of Integrated Research, Institute of Science Tokyo, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan.
The chirality of helical polypeptides is correlated to that of their constituent amino acid residues. For polypeptides with non-natural backbones, however, such correlations are less clear. Here, circular double helices with torus knot/link topologies were assembled from non-natural metal-peptide chains composed of Ag(I) ions and ditopic tripeptides with Gly-Gly-Ala and Gly-Ala-Gly sequences.
View Article and Find Full Text PDFLangmuir
March 2025
Molecular Complexity Laboratory, Department of Chemistry, Raiganj University, Raiganj, West Bengal 733134, India.
Induction of chirality to nanosized superstructures from hierarchical self-assembly of achiral monomeric units is an important area to understand the natural chiral amplification and evolution of life processes. We report herein that the complexation of salicylaldehyde azine, 1,2-bis(2-(benzyloxy)benzylidene)hydrazine (BSAZ), with β-cyclodextrin (β-CD) in aqueous solution results in the formation of a slipped J-aggregate (θ < 54.7°) that aggregates further into a left-handed superhelix through sterical constraints triggered by the hydrophobic effect.
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