Chemische Evolution eines bakteriellen Proteoms

Non-canonical Amino Acid Substrates of E. coli Aminoacyl-tRNA Synthetases

In this comprehensive review, I focus on the twenty E. coli aminoacyl-tRNA synthetases and their ability to charge non-canonical amino acids (ncAAs) onto tRNAs. The promiscuity of these enzymes has been harnessed for diverse applications including understanding and engineering of protein function, creation of organisms with an expanded genetic code, and the synthesis of diverse peptide libraries for drug discovery. The review catalogues the structures of all known ncAA substrates for each of the 20 E. coli aminoacyl-tRNA synthetases, including ncAA substrates for engineered versions of these enzymes. Drawing from the structures in the list, I highlight trends and novel opportunities for further exploitation of these ncAAs in the engineering of protein function, synthetic biology, and in drug discovery.

Noncanonical Amino Acids in Synthetic Biosafety and Post-translational Modification Studies

The incorporation of noncanonical amino acids (ncAAs) has been extensively studied because of its broad applicability. In the past decades, various in vitro and in vivo ncAA incorporation approaches have been developed to generate synthetic recombinant proteins. Herein, we discuss the methodologies for ncAA incorporation, and their use in diverse research areas, such as in synthetic biosafety and for studies of post-translational modifications.

Expanding the DOPA Universe with Genetically Encoded, Mussel-Inspired Bioadhesives for Material Sciences and Medicine

Catechols are a biologically relevant group of aromatic diols that have attracted much attention as mediators of adhesion of "bio-glue" proteins in mussels of the genus Mytilus. These organisms use catechols in the form of the noncanonical amino acid l-3,4-dihydroxyphenylalanine (DOPA) as a building block for adhesion proteins. The DOPA is generated post-translationally from tyrosine. Herein, we review the properties, natural occurrence, and reactivity of catechols in the design of bioinspired materials. We also provide a basic description of the mussel's attachment apparatus, the interplay between its different molecules that play a crucial role in adhesion, and the role of post-translational modifications (PTMs) of these proteins. Our focus is on the microbial production of mussel foot proteins with the aid of orthogonal translation systems (OTSs) and the use of genetic code engineering to solve some fundamental problems in the bioproduction of these bioadhesives and to expand their chemical space. The major limitation of bacterial expression systems is their intrinsic inability to introduce PTMs. OTSs have the potential to overcome these challenges by replacing canonical amino acids with noncanonical ones. In this way, PTM steps are circumvented while the genetically programmed precision of protein sequences is preserved. In addition, OTSs should enable spatiotemporal control over the complex adhesion process, because the catechol function can be masked by suitable chemical protection. Such caged residues can then be noninvasively unmasked by, for example, UV irradiation or thermal treatment. All of these features make OTSs based on genetic code engineering in reprogrammed microbial strains new and promising tools in bioinspired materials science.

Synthetic Biology-The Synthesis of Biology

Synthetic biology concerns the engineering of man-made living biomachines from standardized components that can perform predefined functions in a (self-)controlled manner. Different research strategies and interdisciplinary efforts are pursued to implement engineering principles to biology. The "top-down" strategy exploits nature's incredible diversity of existing, natural parts to construct synthetic compositions of genetic, metabolic, or signaling networks with predictable and controllable properties. This mainly application-driven approach results in living factories that produce drugs, biofuels, biomaterials, and fine chemicals, and results in living pills that are based on engineered cells with the capacity to autonomously detect and treat disease states in vivo. In contrast, the "bottom-up" strategy seeks to be independent of existing living systems by designing biological systems from scratch and synthesizing artificial biological entities not found in nature. This more knowledge-driven approach investigates the reconstruction of minimal biological systems that are capable of performing basic biological phenomena, such as self-organization, self-replication, and self-sustainability. Moreover, the syntheses of artificial biological units, such as synthetic nucleotides or amino acids, and their implementation into polymers inside living cells currently set the boundaries between natural and artificial biological systems. In particular, the in vitro design, synthesis, and transfer of complete genomes into host cells point to the future of synthetic biology: the creation of designer cells with tailored desirable properties for biomedicine and biotechnology.

All about that Amide Bond: The Sixth Chemical Protein Synthesis (CPS) Meeting

Endless potential: The sixth Chemical Protein Synthesis Meeting, held recently in St. Augustine, Florida, showed the potential of peptide and protein chemistry when applied toward understanding and controlling complex biological processes. This report highlights the diverse and cutting-edge protein chemistry presented at the meeting.