We report the template-directed synthesis of a π-conjugated 14-porphyrin nanoball. This structure consists of two intersecting nanorings containing six and 10 porphyrin units. Fluorescence upconversion spectroscopy experiments demonstrate that electronic excitation delocalizes over the whole three-dimensional π system in less than 0.3 ps if the nanoball is bound to its templates or over 2 ps if the nanoball is empty.
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http://dx.doi.org/10.1021/jacs.8b02552 | DOI Listing |
Chemistry
December 2024
Organocatalysis Research Group, Institute of Organic Chemistry, HUN-REN Research Centre for Natural Sciences, 2. Magyar tudósok krt., H-1117, Budapest, Hungary.
A concise, bioinspired, and enantioselective synthesis of (-)-hunterine A, an odd 6/7/6/6/5 pentacyclic natural product, is described. The key step in the synthesis of this complex structure is an interim-template directed 6-exo selective epoxide ring-opening reaction, which is interwoven with a hydrolysis step of the indolenine hemiaminal template to create the unusual 7-membered azepine bridge motif. Our work not only refines the previously proposed biogenetic pathway, but also reveals the possible stereochemical prerequisite of the unique skeletal rearrangement, which provides a vantage point for understanding how (-)-hunterine A is likely to be generated in nature.
View Article and Find Full Text PDFPhys Life Rev
December 2024
Research Center for Advanced Science and Technology, University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo 153-8904, Japan.
Enormous progress has been made in the last 20 years since the publication of our review [1] in this journal on transport and traffic phenomena in biology. In this brief article we present a glimpse of the major advances during this period. First, we present similarities and differences between collective intracellular transport of a single micron-size cargo by multiple molecular motors and that of a cargo particle by a team of ants on the basis of the common principle of load-sharing.
View Article and Find Full Text PDFChem Commun (Camb)
November 2024
State Key Laboratory of Mesoscience and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
A template-directed synthesis of one-dimensional hexagonal PdTe nanowires using Te nanowires as a template through a two-step hydrothermal process is developed, which exhibit excellent mass activity of 4.4 A mg for ethanol electrooxidation in an alkaline medium. This work enriches the controlled synthesis of one-dimensional noble metal chalcogenide nanomaterials.
View Article and Find Full Text PDFCold Spring Harb Perspect Biol
November 2024
Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
In recent years, significant advances have been made in understanding the intricate details of the mechanisms underlying alternative lengthening of telomeres (ALT). Studies of a specialized DNA strand break repair mechanism, known as break-induced replication, and the advent of telomere-specific DNA damaging strategies and proteomic methodologies to profile the ribonucleoprotein composition of telomeres enabled the discovery of networks of proteins that coordinate the stepwise homology-directed DNA repair and DNA synthesis processes of ALT. These networks couple mediators of homologous recombination, DNA template-switching, long-range template-directed DNA synthesis, and DNA strand resolution with SUMO-dependent liquid condensate formation to create discrete nuclear bodies where telomere extension occurs.
View Article and Find Full Text PDFCommun Biol
October 2024
Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.
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