Such an approach was routinely adopted in scanning electron microscopy to improve the electron mobility between nanoparticles and substrate. Elimination of heterogeneous contacts ensured that the electrochemical activity of single nanoparticles can be accessed and further correlated with their structural features, thus paving the way for single nanoparticle electrochemistry to deliver on its promises in SAR.Sulfide quinone oxidoreductase (SQOR) catalyzes the first step in sulfide clearance, coupling H2S oxidation to coenzyme Q reduction. Recent structures of human SQOR revealed a sulfur atom bridging the SQOR active site cysteines in a trisulfide configuration. Here, we assessed the importance of this cofactor using kinetic, crystallographic, and computational modeling approaches. Cyanolysis of SQOR proceeds via formation of an intense charge transfer complex that subsequently decays to eliminate thiocyanate. We captured a disulfanyl-methanimido thioate intermediate in the SQOR crystal structure, revealing how cyanolysis leads to reversible loss of SQOR activity that is restored in the presence of sulfide. Computational modeling and MD simulations revealed an ∼105-fold rate enhancement for nucleophilic addition of sulfide into the trisulfide versus a disulfide cofactor. The cysteine trisulfide in SQOR is thus critical for activity and provides a significant catalytic advantage over a cysteine disulfide.Sulfur and selenium occupy a distinguished position in biology owing to their redox activities, high nucleophilicity, and acyl transfer capabilities. Thiolated/selenolated amino acids, including cysteine, selenocysteine, and their derivatives, play critical roles in regulating the conformation and function of proteins and serve as an important motif for peptide design and bioconjugation. Unfortunately, a general and concise method to attain enantiopure β-thiolated/selenolated amino acids remains an unsolved problem. Herein, we present a photoredox-catalyzed asymmetric method for the preparation of enantiopure β-thiolated/selenolated amino acids using a simple chiral auxiliary, which controls the diastereoselectivity of the key alkylation step and acts as an orthogonal protecting group in the subsequent peptide synthesis. Our protocol can be used to prepare a wide range of β-thiolated/selenolated amino acids on a gram scale, which would otherwise be difficult to obtain using conventional methods. The effect of our chemistry was further highlighted and validated through the preparation of a series of peptidyl thiol/selenol analogues, including cytochrome c oxidase subunit protein 7C and oxytocin.Within the broad research efforts to engineer chemical pathways to yield high-throughput evolutionary synthesis of genes and their screening for dictated functionalities, we introduce the evolution of nucleic-acid-based constitutional dynamic networks (CDNs) that follow reproduction/variation/selection principles. These fundamental principles are demonstrated by assembling a library of nucleic-acid strands and hairpins as functional modules for evolving networks. Primary T1-initiated selection of components from the library assembles a parent CDN X, where the evolved constituents exhibit catalytic properties to cleave the hairpins in the library. Cleavage of the hairpins yields fragments, which reproduces T1 to replicate CDN X, whereas the other fragments T2 and T3 select other components to evolve two other CDNs, Y and Z (variation). By applying appropriate counter triggers, we demonstrate the guided selection of networks from the evolved CDNs. By integrating additional hairpin substrates into the system, CDN-dictated emergent catalytic transformations are accomplished. The study provides pathways to construct evolutionary dynamic networks revealing enhanced gated and cascaded functions.In living systems, fuel-driven assembly is ubiquitous, and examples include the formation of microtubules or actin bundles. These structures have inspired researchers to develop synthetic counterparts, leading to exciting new behaviors in man-made structures. However, most of these examples are serendipitous discoveries because clear design rules do not yet exist. In this work, we show design rules to drive peptide self-assembly regulated by a fuel-driven reaction cycle. We demonstrate that, by altering the ratio of attractive to repulsive interactions between peptides, the behavior can be toggled between no assembly, fuel-driven dissipative self-assembly, and a state in which the system is permanently assembled. These rules can be generalized for other peptide sequences. In addition, our finding is explained in the context of the energy landscapes of self-assembly. We anticipate that our design rules can further aid the field and help the development of autonomous materials with life-like properties.Realizing robust DNA functionalization with strict valence control in the sub-2-nm thiolate-protected luminescent gold nanoparticles (AuNPs) is highly demanded but remains unsolved due to their unique Au(0) core and Au(I)-S shell structures. Herein, we report a facile strategy using phosphorothioates (ps)-modified DNA (psDNA) as a template for in situ growth of near-infrared (NIR)-emitting AuNPs with precisely controlled DNA valence. https://www.selleckchem.com/Bcl-2.html In addition, the particle size could be finely tuned in ultrasmall ranges from 1.3 to 2.6 nm with regulation of the ps length of psDNA. The ultrasmall NIR-emitting AuNPs bearing strict DNA valence are also demonstrated to be as powerful building block for well-organized one-dimensional assembly and optical probe for targeted cellular imaging. Such a facile strategy in decoration of luminescent AuNPs with strict DNA valence provides a new pathway for development of surface-functionalizable ultrasmall metal nanoplatforms toward various downstream applications.Here, we reported for the first time a mechanistically distinctive cobalt-catalyzed Markovnikov-type sequential semihydrogenation/hydrohydrazidation of aliphatic terminal alkynes in one pot. A cobalt hydride species was employed as two roles for both a unique metal-catalyzed Markovnikov-type insertion of the aliphatic terminal alkynes and then metal-catalyzed hydrogen atom transfer of alkenes. This operationally simple protocol exhibits excellent functional group tolerance and step economy. The hydrazone products could be easily transferred to various valuable amine derivatives.