Methionine epimerization in cyclic peptides

Pramodkumar D. Jadhav; Jianheng Shen; Peta-Gaye Burnett; Jian Yang; Ramaswami Sammynaiken; Martin J. T. Reaney

doi:10.1039/d1ra04260b

A one-step biofunctionalization strategy of electrospun scaffolds enables spatially selective presentation of biological cues

10.1101/850875 ◽

2019 ◽

Author(s):

Paul Wieringa ◽

Andre Girao ◽

Roman Truckenmuller ◽

Alexander Welle ◽

Silvestro Micera ◽

...

Keyword(s):

Extracellular Matrix ◽

Regenerative Medicine ◽

Dorsal Root ◽

Neurite Growth ◽

Electrospun Scaffolds ◽

Selective Functionalization ◽

Promising Strategy ◽

Reactive Groups ◽

Spatial Domains ◽

One Step

AbstractTo recapitulate the heterogeneous complexity of tissues in our body with synthetic mimics of the extracellular matrix (ECM), it is important to develop methods that can easily allow the selective functionalization of defined spatial domains. Here, we introduce a facile method to functionalize microfibrillar meshes with different reactive groups able to bind biological moieties in a one-step reaction. The resulting scaffolds proved to selectively support a differential neurite growth after being seeded with dorsal root ganglia. Considering the general principles behind the method developed, this is a promising strategy to realize enhanced biomimicry of native ECM for different regenerative medicine applications.

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One-Step Synthesis of a Unique Molecular Platform for the Selective Functionalization of Calix[6]arenes

Synthesis ◽

10.1055/s-0036-1588681 ◽

2017 ◽

Vol 49 (05) ◽

pp. 1009-1023

Author(s):

Ivan Jabin ◽

Roy Lavendomme ◽

Volodymyr Malytskyi ◽

Jeremy Vandermeersch ◽

Michel Luhmer

Keyword(s):

Selective Functionalization ◽

One Step

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Use of polymers as protecting groups in organic synthesis. III. Selective functionalization of polyhydroxy alcohols

Canadian Journal of Chemistry ◽

10.1139/v76-134 ◽

1976 ◽

Vol 54 (6) ◽

pp. 926-934 ◽

Cited By ~ 64

Author(s):

Jean M. J. Fréchet ◽

Lucy J. Nuyens

Keyword(s):

Acidic Medium ◽

Functional Group ◽

Primary Alcohol ◽

Protecting Groups ◽

Hydroxyl Groups ◽

Ether Linkage ◽

Reaction Conditions ◽

Selective Functionalization ◽

One Step ◽

Insoluble Polymers

Insoluble polymers containing trityl chloride residues were used to block one primary alcohol functional group of several polyhydroxy alcohols. After protecting the remaining hydroxyl groups by benzoylation, the ether linkage between the polymer and the protected alcohol was cleaved in acidic medium. Depending on the reaction conditions and the nature of the starting alcohol, several alcohols or bromides in which only one of the two primary hydroxyls had been esterified, were obtained. In some cases benzoyl migrations were observed. The trityl chloride polymers could be regenerated in one step without degradation or appreciable loss of activity.

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Macrocyclization of peptidoarylacetamides with self-assembly properties through late-stage palladium-catalyzed C(sp2)▬H olefination

Science Advances ◽

10.1126/sciadv.aaw0323 ◽

2019 ◽

Vol 5 (3) ◽

pp. eaaw0323 ◽

Cited By ~ 9

Author(s):

Jiantao Tan ◽

Jie Wu ◽

Shu Liu ◽

Hequan Yao ◽

Huan Wang

Keyword(s):

Self Assembly ◽

Late Stage ◽

Cyclic Peptides ◽

Cross Link ◽

Selective Functionalization ◽

Palladium Catalyzed ◽

Material Sciences ◽

Facile Preparation ◽

Metal Catalyzed ◽

Site Selective

Peptide macrocycles often display diverse bioactivities and self-assembly properties, which lead to a variety of applications in medicinal and material sciences. Transition metal–catalyzed C▬H activations are emerging strategies for site-selective functionalization of amino acids and peptides, as well as the construction of cyclic peptides. Here, we report the development of a peptide-directed method for the macrocyclization of peptidoarylacetamides by Pd(II)-catalyzed late-stage C(sp2)▬H olefination. In this protocol, peptide backbones act as internal directing groups and enable facile preparation of diverse cyclic peptides that are difficult to synthesize by conventional macrolactamization. Furthermore, we show that the incorporation of aryl-alkene cross-link in the backbone constrains cyclic peptides into conformations for self-assembly.

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A General Strategy for the Synthesis of Rare Sugars via Ru(II)-catalyzed and Boron-mediated Selective Epimerization of 1,2-trans-diols to 1,2-cis-diols

10.26434/chemrxiv-2021-67sx5 ◽

2021 ◽

Author(s):

Xiaolei Li ◽

Jicheng Wu ◽

Weiping Tang

Keyword(s):

Natural Products ◽

Building Blocks ◽

The Other ◽

General Strategy ◽

Biological Processes ◽

Boronate Esters ◽

Selective Functionalization ◽

Efficient Construction ◽

One Step ◽

Rare Sugars

Human glycans are primarily composed of nine common sugar building blocks. On the other hand, several hundred monosaccharides have been discovered in bacteria and most of them are not readily available. The ability to access these rare sugars and the corresponding glycocon-jugates can facilitate the studies of various fundamentally important biological processes in bacteria, including interactions between microbiota and the human host. Many rare sugars also exist in a variety of natural products and pharmaceutical reagents with significant biological activi-ties. Although methods have been developed for the synthesis of rare monosaccharides, most of them involve lengthy steps. Herein we report an efficient and general strategy that can provide access to rare sugars from commercially available common monosaccharides via a one-step Ru(II)-catalyzed and boron-mediated selective epimerization of 1,2-trans-diols to 1,2-cis-diols. The formation of boronate esters drives the equilibrium towards 1,2-cis-diol products, which can be immediately used for further selective functionalization and glycosylation. The utility of this strategy was demonstrated by the efficient construction of glycoside skeletons in natural products or bioactive compounds.

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An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092670 ◽

1976 ◽

Vol 34 ◽

pp. 542-543

Author(s):

R.P. Goehner ◽

W.T. Hatfield ◽

Prakash Rao

Keyword(s):

Electron Diffraction ◽

Real Time ◽

Pattern Analysis ◽

Flow Diagram ◽

Hard Copy ◽

Time Analysis ◽

Real Time Analysis ◽

Transmission Electron ◽

One Step ◽

Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

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Nutrient-regulated gene expression in eukaryotes

Biochemical Society Symposium ◽

10.1042/bss0730085 ◽

2006 ◽

Vol 73 ◽

pp. 85-96 ◽

Cited By ~ 8

Author(s):

Richard J. Reece ◽

Laila Beynon ◽

Stacey Holden ◽

Amanda D. Hughes ◽

Karine Rébora ◽

...

Keyword(s):

Gene Expression ◽

Rna Polymerase ◽

Rna Polymerase Ii ◽

Transcriptional Control ◽

Direct Interaction ◽

Signalling Pathways ◽

A Cell ◽

One Step ◽

Higher Eukaryotes ◽

Regulated Gene Expression

The recognition of changes in environmental conditions, and the ability to adapt to these changes, is essential for the viability of cells. There are numerous well characterized systems by which the presence or absence of an individual metabolite may be recognized by a cell. However, the recognition of a metabolite is just one step in a process that often results in changes in the expression of whole sets of genes required to respond to that metabolite. In higher eukaryotes, the signalling pathway between metabolite recognition and transcriptional control can be complex. Recent evidence from the relatively simple eukaryote yeast suggests that complex signalling pathways may be circumvented through the direct interaction between individual metabolites and regulators of RNA polymerase II-mediated transcription. Biochemical and structural analyses are beginning to unravel these elegant genetic control elements.

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