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Introduction of α-N-methylated non-proteinogenic amino acids into peptides can improve their biological activities, membrane permeability and proteolytic stability. This is commonly achieved, in nature and in the lab, by assembling pre-methylated amino acids. The more appealing route of methylating amide bonds is challenging. Biology has evolved an α-N-automethylating enzyme, OphMA, which acts on the amide bonds of peptides fused to its C-terminus. Due to the ribosomal biosynthesis of its substrate, the activity of this enzyme towards peptides with non-proteinogenic amino acids has not been addressed. An engineered OphMA, intein-mediated protein ligation and solid-phase peptide synthesis have allowed us to demonstrate the methylation of amide bonds in the context of non-natural amides. This approach may have application in the biotechnological production of therapeutic peptides., (© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The emergence of high-throughput DNA sequencing technologies sparked a revolution in the field of genomics that has rippled into many branches of the life and physical sciences. The remarkable sensitivity, specificity, throughput, and multiplexing capacity that are inherent to parallel DNA sequencing have since motivated its use as a broad-spectrum molecular counter. A key aspect of extrapolating DNA sequencing to non-traditional applications is the need to append nucleic-acid barcodes to entities of interest. In this review, we describe the chemical and biochemical approaches that have enabled nucleic-acid barcoding of proteinaceous and non-proteinaceous materials and provide examples of downstream technologies that have been made possible by DNA-encoded molecules. As commercially available high-throughput sequencers were first released less than 15 years ago, we believe related applications will continue to mature and close by proposing new frontiers to support this assertion., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Eukaryotic genomes are dynamically regulated through a host of epigenetic stimuli. The substrate for these epigenetic transactions, chromatin, is a polymer of nucleosome building blocks. In native chromatin, each nucleosome can differ from its neighbors as a result of covalent modifications to both the DNA and the histone packaging proteins. The heterotypic nature of chromatin presents a formidable obstacle to biochemical studies seeking to understand the role of context on epigenetic regulation. A chemical approach to the production of heterotypic chromatin that can be used in such studies is introduced. This method involves the attachment of a user-defined modified histone peptide to a designated nucleosome within the polymer by using a peptide nucleic acid (PNA) targeting compound. This strategy was applied to dissect the effect of chromatin context on the activity of the histone methyltransferase PRC2. The results show that PRC2 can be stimulated to produce histone H3 methylation from a defined nucleation site., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Split inteins carry out a naturally occurring process known as protein trans -splicing, where two protein fragments bind to form a catalytically competent enzyme, then catalyze their own excision and the ligation of their flanking sequences. In the past thirteen years since their discovery, chemists and biologists have utilized split inteins in exogenous contexts for a number of biotechnological applications centered around the formation of native peptide bonds. While many protein trans -splicing technologies have emerged and flourished in recent years, several factors still limit their wide-spread practical use. Here, we discuss the development, applications, and limitations of split intein-based technologies and propose that further advancement in this field will require a more fundamental understanding of split intein structure and function.

Extremely fast cyclization of the linear polypeptide precursor 1 takes place to form 2. The reaction appears to be assisted by the native fold of 1, which positions the reactive ends in close proximity. The circular topology has no influence on the folding or function of 2., (© 1998 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.)