共查询到20条相似文献，搜索用时 15 毫秒
1.
Antara Reja Syed Pavel Afrose Dibyendu Das 《Angewandte Chemie (International ed. in English)》2020,59(11):4329-4334
Early evolution benefited from a complex network of reactions involving multiple C?C bond forming and breaking events that were critical for primitive metabolism. Nature gradually chose highly evolved and complex enzymes such as lyases to efficiently facilitate C?C bond formation and cleavage with remarkable substrate selectivity. Reported here is a lipidated short peptide which accesses a homogenous nanotubular morphology to efficiently catalyze C?C bond cleavage and formation. This system shows morphology‐dependent catalytic rates, suggesting the formation of a binding pocket and registered enhancements in the presence of the hydrogen‐bond donor tyrosine, which is exploited by extant aldolases. These assemblies showed excellent substrate selectivity and templated the formation of a specific adduct from a pool of possible adducts. The ability to catalyze metabolically relevant cascade transformations suggests the importance of such systems in early evolution. 相似文献
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Yiming Wang Zhi Xu Matija Lovrak Vincent A. A. le Sage Kai Zhang Xuhong Guo Rienk Eelkema Eduardo Mendes Jan H. van Esch 《Angewandte Chemie (International ed. in English)》2020,59(12):4830-4834
Supramolecular structures with strain‐stiffening properties are ubiquitous in nature but remain rare in the lab. Herein, we report on strain‐stiffening supramolecular hydrogels that are entirely produced through the self‐assembly of synthetic molecular gelators. The involved gelators self‐assemble into semi‐flexible fibers, which thereby crosslink into hydrogels. Interestingly, these hydrogels are capable of stiffening in response to applied stress, resembling biological intermediate filaments system. Furthermore, strain‐stiffening hydrogel networks embedded with liposomes are constructed through orthogonal self‐assembly of gelators and phospholipids, mimicking biological tissues in both architecture and mechanical properties. This work furthers the development of biomimetic soft materials with mechanical responsiveness and presents potentially enticing applications in diverse fields, such as tissue engineering, artificial life, and strain sensors. 相似文献
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Donghui Zhang Qi Chen Wenjing Zhang Hengjiang Liu Jianglin Wan Yuxin Qian Bing Li Songchao Tang Yu Liu Shengfu Chen Runhui Liu 《Angewandte Chemie (International ed. in English)》2020,59(24):9586-9593
The functions of implants like medical devices are often compromised by the host's foreign‐body response (FBR). Herein, we report the development of low‐FBR materials inspired by serine‐rich sericin from silk. Poly‐β‐homoserine (β‐HS) materials consist of the hydrophilic unnatural amino acid β‐homoserine. Self‐assembled monolayers (SAMs) of β‐HS resist adsorption by diverse proteins, as well as adhesion by cells, platelets, and diverse microbes. Experiments lasting up to 3 months revealed that, while implantation with control PEG hydrogels induced obvious inflammatory responses, collagen encapsulation, and macrophage accumulation, these responses were minimal with β‐HS hydrogels. Strikingly, the β‐HS hydrogels induce angiogenesis in implant‐adjacent tissues. Molecular dynamics simulations indicated that the low FBR performance of β‐HS results from what we term “dual hydrogen bonding hydration”, wherein both the backbone amide groups and the sidechain hydroxyl groups of β‐HS undergo hydration. 相似文献
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Donghui Zhang Qi Chen Wenjing Zhang Hengjiang Liu Jianglin Wan Yuxin Qian Bing Li Prof. Songchao Tang Prof. Yu Liu Prof. Shengfu Chen Prof. Runhui Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9673-9680
The functions of implants like medical devices are often compromised by the host's foreign-body response (FBR). Herein, we report the development of low-FBR materials inspired by serine-rich sericin from silk. Poly-β-homoserine (β-HS) materials consist of the hydrophilic unnatural amino acid β-homoserine. Self-assembled monolayers (SAMs) of β-HS resist adsorption by diverse proteins, as well as adhesion by cells, platelets, and diverse microbes. Experiments lasting up to 3 months revealed that, while implantation with control PEG hydrogels induced obvious inflammatory responses, collagen encapsulation, and macrophage accumulation, these responses were minimal with β-HS hydrogels. Strikingly, the β-HS hydrogels induce angiogenesis in implant-adjacent tissues. Molecular dynamics simulations indicated that the low FBR performance of β-HS results from what we term “dual hydrogen bonding hydration”, wherein both the backbone amide groups and the sidechain hydroxyl groups of β-HS undergo hydration. 相似文献
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Dr. Olga V. Makhlynets Pallavi M. Gosavi Prof. Dr. Ivan V. Korendovych 《Angewandte Chemie (International ed. in English)》2016,55(31):9017-9020
We have shown that de novo designed peptides self‐assemble in the presence of copper to create supramolecular assemblies capable of carrying out the oxidation of dimethoxyphenol in the presence of dioxygen. Formation of the supramolecular assembly, which is akin to a protein fold, is critical for productive catalysis since peptides possessing the same functional groups but lacking the ability to self‐assemble do not catalyze substrate oxidation. The ease with which we have discovered robust and productive oxygen activation catalysts suggests that these prion‐like assemblies might have served as intermediates in the evolution of enzymatic function and opens the path for the development of new catalyst nanomaterials. 相似文献
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Dr. Jason Greenwald Michael P. Friedmann Prof. Roland Riek 《Angewandte Chemie (International ed. in English)》2016,55(38):11609-11613
Current theories on the origin of life reveal significant gaps in our understanding of the mechanisms that allowed simple chemical precursors to coalesce into the complex polymers that are needed to sustain life. The volcanic gas carbonyl sulfide (COS) is known to catalyze the condensation of amino acids under aqueous conditions, but the reported di‐, tri‐, and tetra‐peptides are too short to support a regular tertiary structure. Here, we demonstrate that alanine and valine, two of the proteinogenic amino acids believed to have been among the most abundant on a prebiotic earth, can polymerize into peptides and subsequently assemble into ordered amyloid fibers comprising a cross‐β‐sheet quaternary structure following COS‐activated continuous polymerization of as little as 1 mm amino acid. Furthermore, this spontaneous assembly is not limited to pure amino acids, since mixtures of glycine, alanine, aspartate, and valine yield similar structures. 相似文献
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Dr. Wei Ji Shijin Zhang Sachie Yukawa Shogo Onomura Toshio Sasaki Kun'ichi Miyazawa Prof. Dr. Ye Zhang 《Angewandte Chemie (International ed. in English)》2018,57(14):3636-3640
The extracellular matrix (ECM) is the natural fibrous scaffold that regulates cell behavior in a hierarchical manner. By mimicking the dynamic and reciprocal interactions between ECM and cells, higher‐order molecular self‐assembly (SA), mediated through the dynamic growth of scaffold‐like nanostructures assembled by different molecular components, was developed. Designed and synthesized were two self‐sorted coumarin‐based gelators, a peptide molecule and a benzoate molecule, which self‐assemble into nanofibers and nanobelts, respectively, with different dynamic profiles. Upon the dynamic growth of the fibrous scaffold assembled from peptide gelators, nanobelts assembled from benzoate gelators transform into a layer‐by‐layer nanosheet, reaching ninefold increase in height. By using light and an enzyme, the spatial–temporal growth of the scaffold can be modified, leading to in situ height regulation of the higher‐order architecture. 相似文献
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Dr. Marta Tena‐Solsona Dr. Jayanta Nanda Dr. Santiago Díaz‐Oltra Agata Chotera Prof. Gonen Ashkenasy Dr. Beatriu Escuder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6687-6694
We report a series of short peptides possessing the sequence (FE)n or (EF)n and bearing l ‐proline at their N‐terminus that self‐assemble into high aspect ratio aggregates and hydrogels. We show that these aggregates are able to catalyze the aldol reaction, whereas non‐aggregated analogues are catalytically inactive. We have undertaken an analysis of the results, considering the accessibility of catalytic sites, pKa value shifts, and the presence of hydrophobic pockets. We conclude that the presence of hydrophobic regions is indeed relevant for substrate solubilization, but that the active site accessibility is the key factor for the observed differences in reaction rates. The results presented here provide an example of the emergence of a new chemical property caused by self‐assembly, and support the relevant role played by self‐assembled peptides in prebiotic scenarios. In this sense, the reported systems can be seen as primitive aldolase I mimics, and have been successfully tested for the synthesis of simple carbohydrate precursors. 相似文献
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Dr. Natasha Eccles Dr. Flavio della Sala Dr. Bryden A. F. Le Bailly Dr. George F. S. Whitehead Prof. Jonathan Clayden Dr. Simon J. Webb 《ChemistryOpen》2020,9(3):338-345
Two α-aminoisobutyric acid (Aib) foldamers bearing Zn(II)-chelating N-termini have been synthesized and compared with a reported Aib foldamer that has a bis(quinolinyl)/mono(pyridyl) cap (BQPA group). Replacement of the quinolinyl arms of the BQPA-capped foldamer with pyridyl gave a BPPA-capped foldamer, then further replacement of the linking pyridyl with a 1,2,3-triazole gave a BPTA-capped foldamer. Their ability to relay chiral information from carboxylate bound to Zn(II) at the N-terminus to a glycinamide-based NMR reporter of conformational preference at the C-terminus was measured. The importance of the quinolinyl arms became readily apparent, as the foldamers with pyridyl arms were unable to report on the presence of chiral carboxylate in acetonitrile. Low solubility, X-ray crystallography and 1H NMR spectroscopy suggested that interfoldamer interactions inhibited carboxylate binding. However changing solvent to methanol revealed that the end-to-end relay of chiral information could be observed for the Zn(II) complex of the BPTA-capped foldamer at low temperature. 相似文献
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Chenlei Wang Prof. Dr. Jinbo Fei Keqing Wang Prof. Dr. Junbai Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(43):19122-19125
Achieving synthetic architectures with simple structures and robust biomimetic catalytic activities remains a great challenge. Herein, we explore a facile supramolecular assembly approach to construct a dipeptide-based hierarchical nanoarchitecture with enhanced enzyme-like catalytic activity. In this nanoarchitecture, nanospheres are put in a chain-like arrangement through coordination-driven directional self-assembly. The reversible transformation of anisotropic nanochains to isotropic nanospheres switches biomimetic activity. Notably, the assembled nanoarchitecture exhibits a high enzyme-like activity and remarkable long-term stability to promote hydroquinone oxidation, superior to the natural counterpart. This work will pave the way to develop reversible and reusable supramolecular biocatalysts with ordered hierarchical structures for accelerating chemical transformations. 相似文献
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Nuria Rodríguez‐Vázquez Dr. Manuel Amorín Dr. Ignacio Alfonso Prof. Dr. Juan R. Granja 《Angewandte Chemie (International ed. in English)》2016,55(14):4504-4508
A cyclic octapeptide composed of hydroxy‐functionalized γ‐amino acids folds in a “V‐shaped” conformation that allows the selective recognition of anions such as chloride, nitrate, and carbonate. The process involves the simultaneous self‐assembly of six peptide subunits and the recognition of four anions to form a tetrahedral structure, in which the anions are located at the corners of the resulting structure. Each anion is coordinated to three different peptides. The structure was fully characterized by several techniques, including NMR spectroscopy and X‐ray diffraction, and the material was able to facilitate the transmembrane transport of chloride ions. 相似文献
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Jennifer Rodon Fores Miryam Criado‐Gonzalez Alain Chaumont Alain Carvalho Christian Blanck Marc Schmutz Fouzia Boulmedais Pierre Schaaf Loïc Jierry 《Angewandte Chemie (International ed. in English)》2020,59(34):14558-14563
Autocatalysis and self‐assembly are key processes in developmental biology and are involved in the emergence of life. In the last decade both of these features were extensively investigated by chemists with the final goal to design synthetic living systems. Herein, we describe the autonomous growth of a self‐assembled soft material, that is, a supramolecular hydrogel, able to sustain its own formation through an autocatalytic mechanism that is not based on any template effect and emerges from a peptide (hydrogelator) self‐assembly. A domino sequence of events starts from an enzymatically triggered peptide generation followed by self‐assembly into catalytic nanofibers that induce and amplify their production over time, resulting in a 3D hydrogel network. A cascade is initiated by traces (10?18 m ) of a trigger enzyme, which can be localized allowing for a spatial resolution of this autocatalytic buildup of hydrogel growth, an essential condition on the route towards further cell‐mimic designs. 相似文献
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Dr. Zonglin Chu Yanxiao Han Prof. Dr. Petr Král Prof. Dr. Rafal Klajn 《Angewandte Chemie (International ed. in English)》2018,57(24):7023-7027
Confining organic molecules to the surfaces of inorganic nanoparticles can induce intermolecular interactions between them, which can affect the composition of the mixed self‐assembled monolayers obtained by co‐adsorption from solution of two different molecules. Two thiolated ligands (a dialkylviologen and a zwitterionic sulfobetaine) that can interact with each other electrostatically were coadsorbed onto gold nanoparticles. The nanoparticles favor a narrow range of ratios of these two molecules that is largely independent of the molar ratio in solution. Changing the solution molar ratio of the two ligands by a factor of 5 000 affects the on‐nanoparticle ratio of these ligands by only threefold. This behavior is reminiscent of the formation of insoluble inorganic salts (such as AgCl), which similarly compensate positive and negative charges upon crystallizing. Our results pave the way towards developing well‐defined hybrid organic–inorganic nanostructures. 相似文献
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Dr. Charalampos G. Pappas Dr. Nadeesha Wijerathne Dr. Jugal Kishore Sahoo Dr. Ankit Jain Dr. Daniela Kroiss Dr. Ivan R. Sasselli Dr. Ana Sofia Pina Dr. Ayala Lampel Prof. Rein V. Ulijn 《ChemSystemsChem》2020,2(5):e2000013
Dipeptides are known to spontaneously cyclize to diketopiperazines, and in some cases these cyclic dipeptides have been shown to self-assemble to form supramolecular nanostructures. Herein, we demonstrate the in situ cyclization of dipeptide methyl esters in aqueous buffer by intramolecular aminolysis, leading to the formation of diverse supramolecular nanostructures. The chemical nature of the amino acid side chains dictates the supramolecular arrangement and resulting nanoscale architectures. For c[LF], supramolecular gels are formed, and the concentration of starting materials influences the mechanical properties of these hydrogels. Moreover, by adding metalloporphyrins to the starting dipeptide starting solution, these become incorporated through cooperative assembly, resulting in the formation of nanofibers able to catalyse the oxidation of organic phenol in water. The approach taken here, which combines chemically activated assembly with the versatility of short peptides, demonstrates a new and easy method to achieving spontaneous formation of a variety of functional supramolecular materials using simple building blocks. 相似文献
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Lee JH Wernette DP Yigit MV Liu J Wang Z Lu Y 《Angewandte Chemie (International ed. in English)》2007,46(47):9006-9010
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Mareen Pagel Dr. Rayk Hassert Torsten John Prof. Dr. Manfred Wießler Prof. Dr. Bernd Abel Prof. Dr. Annette G. Beck‐Sickinger 《Angewandte Chemie (International ed. in English)》2016,55(15):4826-4830
Promotion of cell adhesion on biomaterials is crucial for the long‐term success of a titanium implant. Herein a novel concept is highlighted combining very stable and affine titanium surface adhesive properties with specific cell binding moieties in one molecule. A peptide containing l ‐3,4‐dihydroxyphenylalanine was synthesized and affinity to titanium was investigated. Modification with a cyclic RGD peptide and a heparin binding peptide (HBP) was realized by an efficient on‐resin combination of Diels–Alder reaction with inverse electron demand and CuI catalyzed azide–alkyne cycloaddition. The peptide was fluorescently labeled by thiol Michael addition. Conjugating the cyclic RGD and HBP in one peptide gave improved spreading, proliferation, viability, and the formation of well‐developed actin cytoskeleton and focal contacts of osteoblast‐like cells. 相似文献
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