Engineered Biosynthesis of β-Alkyl Tryptophan Analogs

<a>Non-canonical amino acids (ncAAs) with dual stereocenters at the α and β positions are valuable precursors to natural products and therapeutics. Despite the potential applications of such bioactive β-branched ncAAs, their availability is limited due to the inefficiency of the multi-step methods used to prepare them. Here we report a stereoselective biocatalytic synthesis of β-branched tryptophan analogs using an engineered variant of Pyrococcus furiosus tryptophan synthase (PfTrpB), PfTrpB7E6. PfTrpB7E6 is the first biocatalyst to synthesize bulky β-branched tryptophan analogs in a single step, with demonstrated access to 27 ncAAs. The molecular basis for the efficient catalysis and broad substrate tolerance of PfTrpB7E6 was explored through X-ray crystallography and UV-visible light spectroscopy, which revealed that a combination of active-site and remote mutations increase the abundance and persistence of a key reactive intermediate. PfTrpB7E6 provides an operationally simple and environmentally benign platform for preparation of β-branched tryptophan building blocks.</a>

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Extended metal-carbohydrate frameworks

Pure and Applied Chemistry ◽

10.1515/pac-2014-0303 ◽

2014 ◽

Vol 86 (9) ◽

pp. 1323-1334 ◽

Cited By ~ 16

Author(s):

Zhichang Liu ◽

J. Fraser Stoddart

Keyword(s):

Materials Science ◽

Metal Organic Frameworks ◽

Building Blocks ◽

Environmentally Benign ◽

Crystalline Materials ◽

The World ◽

Potential Applications ◽

Metal Organic ◽

Industry And Commerce

AbstractCyclodextrins (CDs) – a family of cyclic oligosaccharides – are ideal building blocks for the construction of environmentally benign materials. Herein, we reflect upon the serendipitous discovery of two classes of extended crystalline materials – referred to as cyclodextrin metal-organic frameworks (CD-MOFs) and CD-Bamboo – based on CDs which offer opportunities for potential applications in the world of industry and commerce all the way from sequestering carbon dioxide to extracting gold in an eco-friendly manner. The crucial role of serendipity in scientific research expresses itself two times over at the boundaries between coordination chemistry with materials science.

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Non-Enzymatic Desymmetrization Reactions in Aqueous Media

Symmetry ◽

10.3390/sym13040720 ◽

2021 ◽

Vol 13 (4) ◽

pp. 720

Author(s):

Satomi Niwayama

Keyword(s):

Natural Products ◽

Total Synthesis ◽

Functional Groups ◽

Organic Compounds ◽

Recent Progress ◽

Aqueous Media ◽

Building Blocks ◽

Organic Reactions ◽

Environmentally Benign ◽

Enzymatic Desymmetrization

Symmetric organic compounds are generally obtained inexpensively, and therefore they can be attractive building blocks for the total synthesis of various pharmaceuticals and natural products. The drawback is that discriminating the identical functional groups in the symmetric compounds is difficult. Water is the most environmentally benign and inexpensive solvent. However, successful organic reactions in water are rather limited due to the hydrophobicity of organic compounds in general. Therefore, desymmetrization reactions in aqueous media are expected to offer versatile strategies for the synthesis of a variety of significant organic compounds. This review focuses on the recent progress of desymmetrization reactions of symmetric organic compounds in aqueous media without utilizing enzymes.

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Composite Poly(vinyl alcohol)-Based Nanofibers Embedding Differently-Shaped Gold Nanoparticles: Preparation and Characterization

Polymers ◽

10.3390/polym13101604 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1604

Author(s):

Andrea Dodero ◽

Maila Castellano ◽

Paola Lova ◽

Massimo Ottonelli ◽

Elisabetta Brunengo ◽

...

Keyword(s):

Vinyl Alcohol ◽

Ad Hoc ◽

Chemical Reduction ◽

Chemical Properties ◽

Single Step ◽

Gold Nanostructures ◽

Poly Vinyl Alcohol ◽

Spherical Nanoparticles ◽

Potential Applications ◽

New Perspective

Poly(vinyl alcohol) nanofibrous mats containing ad hoc synthesized gold nanostructures were prepared via a single-step electrospinning procedure and investigated as a novel composite platform with several potential applications. Specifically, the effect of differently shaped and sized gold nanostructures on the resulting mat physical-chemical properties was investigated. In detail, nearly spherical nanoparticles and nanorods were first synthesized through a chemical reduction of gold precursors in water by using (hexadecyl)trimethylammonium bromide as the stabilizing agent. These nanostructures were then dispersed in poly(vinyl alcohol) aqueous solutions to prepare nanofibrous mats, which were then stabilized via a humble thermal treatment able to enhance their thermal stability and water resistance. Remarkably, the nanostructure type was proven to influence the mesh morphology, with the small spherical nanoparticles and the large nanorods leading to thinner well defined or bigger defect-rich nanofibers, respectively. Finally, the good mechanical properties shown by the prepared composite mats suggest their ease of handleability thereby opening new perspective applications.

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Environmentally Benign Route for Scalable Preparation of 1-Imino-3-thioisoindolines−The Key Building Blocks for the Synthesis of Dithio- and Diamino-β-isoindigo Derivatives

The Journal of Organic Chemistry ◽

10.1021/acs.joc.1c00110 ◽

2021 ◽

Vol 86 (6) ◽

pp. 4733-4746

Author(s):

Yuriy V. Zatsikha ◽

Liliya I. Shamova ◽

Victor N. Nemykin

Keyword(s):

Building Blocks ◽

Environmentally Benign

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Laser-Induced Deposition of Plasmonic Ag and Pt Nanoparticles, and Periodic Arrays

Materials ◽

10.3390/ma14010010 ◽

2020 ◽

Vol 14 (1) ◽

pp. 10

Author(s):

Daria V. Mamonova ◽

Anna A. Vasileva ◽

Yuri V. Petrov ◽

Denis V. Danilov ◽

Ilya E. Kolesnikov ◽

...

Keyword(s):

Substrate Surface ◽

Pt Nanoparticles ◽

Single Step ◽

X Ray Diffraction ◽

Ag Nps ◽

X Ray ◽

Periodic Arrays ◽

Potential Applications ◽

Surface Decoration ◽

Wide Potential

Surfaces functionalized with metal nanoparticles (NPs) are of great interest due to their wide potential applications in sensing, biomedicine, nanophotonics, etc. However, the precisely controllable decoration with plasmonic nanoparticles requires sophisticated techniques that are often multistep and complex. Here, we present a laser-induced deposition (LID) approach allowing for single-step surface decoration with NPs of controllable composition, morphology, and spatial distribution. The formation of Ag, Pt, and mixed Ag-Pt nanoparticles on a substrate surface was successfully demonstrated as a result of the LID process from commercially available precursors. The deposited nanoparticles were characterized with SEM, TEM, EDX, X-ray diffraction, and UV-VIS absorption spectroscopy, which confirmed the formation of crystalline nanoparticles of Pt (3–5 nm) and Ag (ca. 100 nm) with plasmonic properties. The advantageous features of the LID process allow us to demonstrate the spatially selective deposition of plasmonic NPs in a laser interference pattern, and thereby, the formation of periodic arrays of Ag NPs forming diffraction grating

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Water-soluble β-aminobisulfonate building blocks for pH and Cu2+ indicators

RSC Advances ◽

10.1039/c6ra17791c ◽

2016 ◽

Vol 6 (88) ◽

pp. 84712-84721 ◽

Cited By ~ 5

Author(s):

Maria A. Cardona ◽

Marina Kveder ◽

Ulrich Baisch ◽

Michael R. Probert ◽

David C. Magri

Keyword(s):

Nmr Spectroscopy ◽

Building Blocks ◽

Water Soluble ◽

Visible Absorption ◽

H Nmr ◽

Uv Visible

Two phenyl β-aminobisulfonate ligands characterised by UV-visible absorption, EPR and 1H NMR spectroscopy exhibit evidence for binding with Cu2+ in water and methanol.

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A Structurally Variable Hinged Tetrahedron Framework from DNA Origami

Journal of Nucleic Acids ◽

10.4061/2011/360954 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 18

Author(s):

David M. Smith ◽

Verena Schüller ◽

Carsten Forthmann ◽

Robert Schreiber ◽

Philip Tinnefeld ◽

...

Keyword(s):

Self Assembly ◽

Gel Electrophoresis ◽

Imaging Techniques ◽

Building Blocks ◽

Dna Origami ◽

Microscopy Technique ◽

Wire Frame ◽

Wide Range ◽

Potential Applications ◽

Linker Molecules

Nanometer-sized polyhedral wire-frame objects hold a wide range of potential applications both as structural scaffolds as well as a basis for synthetic nanocontainers. The utilization of DNA as basic building blocks for such structures allows the exploitation of bottom-up self-assembly in order to achieve molecular programmability through the pairing of complementary bases. In this work, we report on a hollow but rigid tetrahedron framework of 75 nm strut length constructed with the DNA origami method. Flexible hinges at each of their four joints provide a means for structural variability of the object. Through the opening of gaps along the struts, four variants can be created as confirmed by both gel electrophoresis and direct imaging techniques. The intrinsic site addressability provided by this technique allows the unique targeted attachment of dye and/or linker molecules at any point on the structure's surface, which we prove through the superresolution fluorescence microscopy technique DNA PAINT.

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Substantially Transparent Pt, Pd, Rh, And Re Films: Preparation and Properties

MRS Proceedings ◽

10.1557/proc-111-379 ◽

1987 ◽

Vol 111 ◽

Cited By ~ 2

Author(s):

D. E. Aspnes ◽

A. Heller

Keyword(s):

Light Transmission ◽

Building Blocks ◽

Poor Quality ◽

Model Calculations ◽

Transmission Electron ◽

Metal Volume ◽

Potential Applications ◽

Metallic Catalyst ◽

Anomalous Transparency ◽

Best Fit

AbstractFilms of Pt, Pd, Rh, and Re with metal volume fractions of 0.3 to 0.5 have been prepared by mass-transport-limited photoelectrodeposition onto (001) p-InP photocathodes from ∼5 × 10−5 M solutions of the metal ions in 1 M HClO4. These films exhibit their normal catalytic activities (e.g., in hydrogen evolution) and have normal crystal structures, yet are substantially more transparent than equivalent dense films of the same metal loading per unit area. Effective-medium analysis of the spectroellipsometrically measured dielectric functions of these films shows that the anomalous transparency is due to microstructure: depolarization factors and metal packing fractions obtained by best-fit model calculations indicate dendritic (Rh), particulate (Pt, Pd), or platelet (Re) forms that are poorly interconnected in directions parallel to the surface, and whose dimensions are all small compared to the wavelength of light. Transmission electron micrographs confirm these results and reveal that these films consist of primary building blocks of ca. 5 nm crystallites that are organized into relatively loosely packed secondary structures. Potential applications of these films include the formation of efficient metallic-catalyst-coated photoelectrodes on poor-quality semiconductors.

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Cyclic cis-1,3-Diamines Derived from Bicyclic Hydrazines: Synthesis and Applications

Synlett ◽

10.1055/s-0040-1707324 ◽

2020 ◽

Author(s):

Erica Benedetti ◽

Laurent Micouin ◽

Claire Fleurisson

Keyword(s):

Bond Cleavage ◽

Building Blocks ◽

Biologically Active Compounds ◽

Biologically Active ◽

Chemical Similarity ◽

Active Compounds ◽

General Overview ◽

Biological Interest ◽

Potential Applications ◽

Rna Binders

AbstractCyclic cis-1,3-diamines are versatile building blocks frequently found in natural molecules or biologically active compounds. In comparison with widely studied 1,2-diamines, and despite their chemical similarity, 1,3-diamines have been investigated less intensively probably because of a lack of general synthetic procedures giving access to these compounds with good levels of chemo-, regio-, and stereocontrol. In this Account we will give a general overview of the biological interest of cyclic cis-1,3-diamines. We will then describe the synthesis and potential applications of these compounds with a particular focus on the work realized in our laboratory.1 Introduction2 Biological Relevance of the cis-1,3-Diamine Motif3 Classical Synthetic Strategies towards cis-1,3-Diamines4 N–N Bond Cleavage of Bicyclic Hydrazines: A Versatile Method to Access cis-1,3-Diamines4.1 Preparation of Five-Membered Cyclic cis-1,3-Diamino Alcohols4.2 Access to Fluorinated 1,3-cis-Diaminocyclopentanes4.3 Synthesis of cis-1,3-Diaminocyclohexitols4.4 Formation of Cyclic cis-3,5-Diaminopiperidines5 Applications of Cyclic cis-1,3-Diamines5.1 Small-Molecular RNA Binders5.2 Fluorinated 1,3-Diamino Cyclopentanes as NMR Probes6 Concluding Remarks

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